diff --git a/src/calendar.c b/src/calendar.c
index 2286f265..46e036b4 100644
--- a/src/calendar.c
+++ b/src/calendar.c
@@ -499,7 +499,7 @@ get_month_abbrev(char const *mon)
 {
     static char buf[80];
 #ifndef REM_USE_WCHAR
-    sprintf(buf, "%.3s", mon);
+    snprintf(buf, sizeof(buf), "%.3s", mon);
     return buf;
 #else
     char *s;
@@ -626,9 +626,9 @@ Colorize256(int r, int g, int b, int bg, int clamp)
         }
     }
     if (bg) {
-        sprintf(buf, "\x1B[48;5;%dm", best);
+        snprintf(buf, sizeof(buf), "\x1B[48;5;%dm", best);
     } else {
-        sprintf(buf, "\x1B[38;5;%dm", best);
+        snprintf(buf, sizeof(buf), "\x1B[38;5;%dm", best);
     }
     return buf;
 }
@@ -641,9 +641,9 @@ ColorizeTrue(int r, int g, int b, int bg, int clamp)
         ClampColor(&r, &g, &b);
     }
     if (bg) {
-        sprintf(buf, "\x1B[48;2;%d;%d;%dm", r, g, b);
+        snprintf(buf, sizeof(buf), "\x1B[48;2;%d;%d;%dm", r, g, b);
     } else {
-        sprintf(buf, "\x1B[38;2;%d;%d;%dm", r, g, b);
+        snprintf(buf, sizeof(buf), "\x1B[38;2;%d;%d;%dm", r, g, b);
     }
     return buf;
 }
@@ -1812,7 +1812,7 @@ static void WriteCalHeader(void)
     int y, m, d;
 
     FromDSE(DSEToday, &y, &m, &d);
-    sprintf(buf, "%s %d", get_month_name(m), y);
+    snprintf(buf, sizeof(buf), "%s %d", get_month_name(m), y);
 
     WriteTopCalLine();
 
@@ -2016,7 +2016,7 @@ static int DoCalRem(ParsePtr p, int col)
         trig.typ == MSF_TYPE) {
         if (PsCal && is_color) {
             char cbuf[24];
-            sprintf(cbuf, "%d %d %d ", col_r, col_g, col_b);
+            snprintf(cbuf, sizeof(cbuf), "%d %d %d ", col_r, col_g, col_b);
             DBufPuts(&pre_buf, cbuf);
             strcpy(trig.passthru, "COLOR");
             /* Don't change trig.typ or next if() will trigger! */
@@ -2149,7 +2149,7 @@ static int DoCalRem(ParsePtr p, int col)
         if (trig.typ != PASSTHRU_TYPE &&
             UserFuncExists("calprefix")==1) {
             char evalBuf[64];
-            sprintf(evalBuf, "calprefix(%d)", trig.priority);
+            snprintf(evalBuf, sizeof(evalBuf), "calprefix(%d)", trig.priority);
             s2 = evalBuf;
             r = EvalExpr(&s2, &v, NULL);
             if (!r) {
@@ -2192,7 +2192,7 @@ static int DoCalRem(ParsePtr p, int col)
         if (trig.typ != PASSTHRU_TYPE &&
             UserFuncExists("calsuffix")==1) {
             char evalBuf[64];
-            sprintf(evalBuf, "calsuffix(%d)", trig.priority);
+            snprintf(evalBuf, sizeof(evalBuf), "calsuffix(%d)", trig.priority);
             s2 = evalBuf;
             r = EvalExpr(&s2, &v, NULL);
             if (!r) {
@@ -2736,7 +2736,7 @@ CalendarTime(int tim, int duration)
     else              hh2 = h2;
 
     if (days) {
-        sprintf(daybuf, "+%d", days);
+        snprintf(daybuf, sizeof(daybuf), "+%d", days);
     } else {
         daybuf[0] = 0;
     }
@@ -2759,12 +2759,12 @@ CalendarTime(int tim, int duration)
 
     switch(ScFormat) {
     case SC_AMPM:
-        sprintf(buf, "%d%c%02d%s-%d%c%02d%s%s ",
+        snprintf(buf, sizeof(buf), "%d%c%02d%s-%d%c%02d%s%s ",
                 hh, TimeSep, min, ampm1, hh2, TimeSep, min2, ampm2, daybuf);
         break;
 
     case SC_MIL:
-        sprintf(buf, "%02d%c%02d-%02d%c%02d%s ",
+        snprintf(buf, sizeof(buf), "%02d%c%02d-%02d%c%02d%s ",
                 h, TimeSep, min, h2, TimeSep, min2, daybuf);
         break;
     }
@@ -2796,7 +2796,7 @@ char const *SimpleTime(int tim)
             if (h == 0) hh=12;
             else if (h > 12) hh=h-12;
             else hh=h;
-            sprintf(buf, "%d%c%02d%.64s ", hh, TimeSep, min, (h>=12) ? tr("pm") : tr("am"));
+            snprintf(buf, sizeof(buf), "%d%c%02d%.64s ", hh, TimeSep, min, (h>=12) ? tr("pm") : tr("am"));
         }
         break;
 
@@ -2804,7 +2804,7 @@ char const *SimpleTime(int tim)
         if (tim != NO_TIME) {
             h = tim / 60;
             min = tim % 60;
-            sprintf(buf, "%02d%c%02d ", h, TimeSep, min);
+            snprintf(buf, sizeof(buf), "%02d%c%02d ", h, TimeSep, min);
         }
         break;
     }
@@ -2856,7 +2856,7 @@ char const *SynthesizeTag(void)
     MD5Init(&ctx);
     MD5Update(&ctx, (unsigned char *) CurLine, strlen(CurLine));
     MD5Final(buf, &ctx);
-    sprintf(out, "__syn__%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
+    snprintf(out, sizeof(out), "__syn__%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x%02x",
             (unsigned int) buf[0], (unsigned int) buf[1],
             (unsigned int) buf[2], (unsigned int) buf[3],
             (unsigned int) buf[4], (unsigned int) buf[5],
diff --git a/src/dorem.c b/src/dorem.c
index 1ce6a9aa..2dfacb61 100644
--- a/src/dorem.c
+++ b/src/dorem.c
@@ -1180,7 +1180,7 @@ int TriggerReminder(ParsePtr p, Trigger *t, TimeTrig *tim, int dse, int is_queue
             return OK;
         }
         FromDSE(dse, &y, &m, &d);
-        sprintf(tmpBuf, "%04d/%02d/%02d ", y, m+1, d);
+        snprintf(tmpBuf, sizeof(tmpBuf), "%04d/%02d/%02d ", y, m+1, d);
         if (DBufPuts(&calRow, tmpBuf) != OK) {
             DBufFree(&calRow);
             DBufFree(&pre_buf);
@@ -1201,9 +1201,9 @@ int TriggerReminder(ParsePtr p, Trigger *t, TimeTrig *tim, int dse, int is_queue
                 DBufPuts(&calRow, "* ");
             }
             if (tim->duration != NO_TIME) {
-                sprintf(tmpBuf, "%d ", tim->duration);
+                snprintf(tmpBuf, sizeof(tmpBuf), "%d ", tim->duration);
             } else {
-                sprintf(tmpBuf, "* ");
+                snprintf(tmpBuf, sizeof(tmpBuf), "* ");
             }
             if (DBufPuts(&calRow, tmpBuf) != OK) {
                 DBufFree(&calRow);
@@ -1211,9 +1211,9 @@ int TriggerReminder(ParsePtr p, Trigger *t, TimeTrig *tim, int dse, int is_queue
                 return E_NO_MEM;
             }
             if (tim->ttime != NO_TIME) {
-                sprintf(tmpBuf, "%d ", tim->ttime);
+                snprintf(tmpBuf, sizeof(tmpBuf), "%d ", tim->ttime);
             } else {
-                sprintf(tmpBuf, "* ");
+                snprintf(tmpBuf, sizeof(tmpBuf), "* ");
             }
             if (DBufPuts(&calRow, tmpBuf) != OK) {
                 DBufFree(&calRow);
@@ -1263,7 +1263,7 @@ int TriggerReminder(ParsePtr p, Trigger *t, TimeTrig *tim, int dse, int is_queue
     /* Don't use msgprefix() on RUN-type reminders */
     if (t->typ != RUN_TYPE) {
         if (UserFuncExists("msgprefix") == 1) {
-            sprintf(PrioExpr, "msgprefix(%d)", t->priority);
+            snprintf(PrioExpr, sizeof(PrioExpr), "msgprefix(%d)", t->priority);
             s = PrioExpr;
             r = EvalExpr(&s, &v, NULL);
             if (!r) {
@@ -1289,7 +1289,7 @@ int TriggerReminder(ParsePtr p, Trigger *t, TimeTrig *tim, int dse, int is_queue
 
     if (t->typ != RUN_TYPE) {
         if (UserFuncExists("msgsuffix") == 1) {
-            sprintf(PrioExpr, "msgsuffix(%d)", t->priority);
+            snprintf(PrioExpr, sizeof(PrioExpr), "msgsuffix(%d)", t->priority);
             s = PrioExpr;
             r = EvalExpr(&s, &v, NULL);
             if (!r) {
@@ -1694,7 +1694,7 @@ static int ShouldTriggerBasedOnWarn(Trigger *t, int dse, int *err)
         return (dse == DSEToday);
     }
     for (i=1; ; i++) {
-        sprintf(buffer, "%s(%d)", t->warn, i);
+        snprintf(buffer, sizeof(buffer), "%s(%d)", t->warn, i);
         s = buffer;
         r = EvalExpr(&s, &v, NULL);
         if (r) {
diff --git a/src/expr.c b/src/expr.c
index 5e23addc..fec822a8 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -3014,12 +3014,12 @@ int DoCoerce(char type, Value *v)
         }
     case STR_TYPE:
         switch(v->type) {
-        case INT_TYPE: sprintf(coerce_buf, "%d", v->v.val); break;
-        case TIME_TYPE: sprintf(coerce_buf, "%02d%c%02d", v->v.val / 60,
+        case INT_TYPE: snprintf(coerce_buf, sizeof(coerce_buf), "%d", v->v.val); break;
+        case TIME_TYPE: snprintf(coerce_buf, sizeof(coerce_buf), "%02d%c%02d", v->v.val / 60,
                                TimeSep, v->v.val % 60);
         break;
         case DATE_TYPE: FromDSE(v->v.val, &y, &m, &d);
-            sprintf(coerce_buf, "%04d%c%02d%c%02d",
+            snprintf(coerce_buf, sizeof(coerce_buf), "%04d%c%02d%c%02d",
                     y, DateSep, m+1, DateSep, d);
             break;
         case DATETIME_TYPE:
@@ -3028,7 +3028,7 @@ int DoCoerce(char type, Value *v)
             k = v->v.val % MINUTES_PER_DAY;
             h = k / 60;
             i = k % 60;
-            sprintf(coerce_buf, "%04d%c%02d%c%02d%c%02d%c%02d",
+            snprintf(coerce_buf, sizeof(coerce_buf), "%04d%c%02d%c%02d%c%02d%c%02d",
                     y, DateSep, m+1, DateSep, d, DateTimeSep, h, TimeSep, i);
             break;
         default: return E_CANT_COERCE;
diff --git a/src/funcs.c b/src/funcs.c
index 0076f637..8ccde36f 100644
--- a/src/funcs.c
+++ b/src/funcs.c
@@ -1076,7 +1076,7 @@ static int FOrd(func_info *info)
     if (u == 1 && t != 11) s = "st";
     if (u == 2 && t != 12) s = "nd";
     if (u == 3 && t != 13) s = "rd";
-    sprintf(buf, "%d%s", v, s);
+    snprintf(buf, sizeof(buf), "%d%s", v, s);
     return RetStrVal(buf, info);
 }
 
@@ -1828,10 +1828,10 @@ static int FTrigger(func_info *info)
 
     FromDSE(date, &y, &m, &d);
     if (tim != NO_TIME) {
-        sprintf(buf, "%d %s %d AT %02d:%02d", d, MonthName[m], y,
+        snprintf(buf, sizeof(buf), "%d %s %d AT %02d:%02d", d, MonthName[m], y,
                 tim/60, tim%60);
     } else {
-        sprintf(buf, "%d %s %d", d, MonthName[m], y);
+        snprintf(buf, sizeof(buf), "%d %s %d", d, MonthName[m], y);
     }
     return RetStrVal(buf, info);
 }
@@ -3012,6 +3012,7 @@ static int FPsshade(func_info *info)
     char psbuff[256];
     char *s = psbuff;
     int i;
+    size_t len = sizeof(psbuff);
 
     /* 1 or 3 args */
     if (Nargs != 1 && Nargs != 3) return E_2MANY_ARGS;
@@ -3027,16 +3028,19 @@ static int FPsshade(func_info *info)
         Wprint(tr("psshade() is deprecated; use SPECIAL SHADE instead."));
     }
 
-    sprintf(s, "/_A LineWidth 2 div def ");
+    snprintf(s, len, "/_A LineWidth 2 div def ");
+    len -= strlen(s);
     s += strlen(s);
-    sprintf(s, "_A _A moveto ");
+    snprintf(s, len, "_A _A moveto ");
+    len -= strlen(s);
     s += strlen(s);
-    sprintf(s, "BoxWidth _A sub _A lineto BoxWidth _A sub BoxHeight _A sub lineto ");
+    snprintf(s, len, "BoxWidth _A sub _A lineto BoxWidth _A sub BoxHeight _A sub lineto ");
+    len -= strlen(s);
     s += strlen(s);
     if (Nargs == 1) {
-        sprintf(s, "_A BoxHeight _A sub lineto closepath %d 100 div setgray fill 0.0 setgray", ARGV(0));
+        snprintf(s, len, "_A BoxHeight _A sub lineto closepath %d 100 div setgray fill 0.0 setgray", ARGV(0));
     } else {
-        sprintf(s, "_A BoxHeight _A sub lineto closepath %d 100 div %d 100 div %d 100 div setrgbcolor fill 0.0 setgray", ARGV(0), ARGV(1), ARGV(2));
+        snprintf(s, len, "_A BoxHeight _A sub lineto closepath %d 100 div %d 100 div %d 100 div setrgbcolor fill 0.0 setgray", ARGV(0), ARGV(1), ARGV(2));
     }
     return RetStrVal(psbuff, info);
 }
@@ -3059,6 +3063,7 @@ static int FPsmoon(func_info *info)
     char const *extra = NULL;
     int size = -1;
     int fontsize = -1;
+    size_t len = sizeof(psbuff);
 
     ASSERT_TYPE(0, INT_TYPE);
     if (ARGV(0) < 0) return E_2LOW;
@@ -3082,60 +3087,71 @@ static int FPsmoon(func_info *info)
         Wprint(tr("psmoon() is deprecated; use SPECIAL MOON instead."));
     }
     if (size > 0) {
-        sprintf(sizebuf, "%d", size);
+        snprintf(sizebuf, sizeof(sizebuf), "%d", size);
     } else {
         strcpy(sizebuf, "DaySize 2 div");
     }
 
     if (fontsize > 0) {
-        sprintf(fontsizebuf, "%d", fontsize);
+        snprintf(fontsizebuf, sizeof(fontsizebuf), "%d", fontsize);
     } else {
         strcpy(fontsizebuf, "EntrySize");
     }
 
-    sprintf(s, "gsave 0 setgray newpath Border %s add BoxHeight Border sub %s sub",
+    snprintf(s, len, "gsave 0 setgray newpath Border %s add BoxHeight Border sub %s sub",
             sizebuf, sizebuf);
+    len -= strlen(s);
     s += strlen(s);
-    sprintf(s, " %s 0 360 arc closepath", sizebuf);
+    snprintf(s, len, " %s 0 360 arc closepath", sizebuf);
+    len -= strlen(s);
     s += strlen(s);
     switch(ARGV(0)) {
     case 0:
-        sprintf(s, " fill");
+        snprintf(s, len, " fill");
+        len -= strlen(s);
         s += strlen(s);
         break;
 
     case 2:
-        sprintf(s, " stroke");
+        snprintf(s, len, " stroke");
+        len -= strlen(s);
         s += strlen(s);
         break;
 
     case 1:
-        sprintf(s, " stroke");
+        snprintf(s, len, " stroke");
+        len -= strlen(s);
         s += strlen(s);
-        sprintf(s, " newpath Border %s add BoxHeight Border sub %s sub",
+        snprintf(s, len, " newpath Border %s add BoxHeight Border sub %s sub",
                 sizebuf, sizebuf);
+        len -= strlen(s);
         s += strlen(s);
-        sprintf(s, " %s 90 270 arc closepath fill", sizebuf);
+        snprintf(s, len, " %s 90 270 arc closepath fill", sizebuf);
+        len -= strlen(s);
         s += strlen(s);
         break;
 
     default:
-        sprintf(s, " stroke");
+        snprintf(s, len, " stroke");
+        len -= strlen(s);
         s += strlen(s);
-        sprintf(s, " newpath Border %s add BoxHeight Border sub %s sub",
+        snprintf(s, len, " newpath Border %s add BoxHeight Border sub %s sub",
                 sizebuf, sizebuf);
+        len -= strlen(s);
         s += strlen(s);
-        sprintf(s, " %s 270 90 arc closepath fill", sizebuf);
+        snprintf(s, len, " %s 270 90 arc closepath fill", sizebuf);
+        len -= strlen(s);
         s += strlen(s);
         break;
     }
     if (extra) {
-        sprintf(s, " Border %s add %s add Border add BoxHeight border sub %s sub %s sub moveto /EntryFont findfont %s scalefont setfont (%s) show",
+        snprintf(s, len, " Border %s add %s add Border add BoxHeight border sub %s sub %s sub moveto /EntryFont findfont %s scalefont setfont (%s) show",
                 sizebuf, sizebuf, sizebuf, sizebuf, fontsizebuf, extra);
+        len -= strlen(s);
         s += strlen(s);
     }
 
-    sprintf(s, " grestore");
+    snprintf(s, len, " grestore");
     return RetStrVal(psbuff, info);
 }
 
@@ -3266,7 +3282,7 @@ static int FDatepart(func_info *info)
  * used for the timezone stuff! */
 static int setenv(char const *varname, char const *val, int overwrite)
 {
-    static char tzbuf[256];
+    static char tzbuf[128];
     if (strcmp(varname, "TZ")) {
         fprintf(ErrFp, "built-in setenv can only be used with TZ\n");
         abort();
@@ -3279,7 +3295,7 @@ static int setenv(char const *varname, char const *val, int overwrite)
     if (strlen(val) > 250) {
         return -1;
     }
-    sprintf(tzbuf, "%s=%s", varname, val);
+    snprintf(tzbuf, sizeof(tzbuf), "%s=%s", varname, val);
     return(putenv(tzbuf));
 }
 #endif
@@ -3288,12 +3304,12 @@ static int setenv(char const *varname, char const *val, int overwrite)
  * used for the timezone stuff! */
 static void unsetenv(char const *varname)
 {
-    static char tzbuf[8];
+    static char tzbuf[128];
     if (strcmp(varname, "TZ")) {
         fprintf(ErrFp, "built-in unsetenv can only be used with TZ\n");
         abort();
     }
-    sprintf(tzbuf, "%s", varname);
+    snprintf(tzbuf, sizeof(tzbuf), "%s", varname);
     putenv(tzbuf);
 }
 #endif
diff --git a/src/json.c b/src/json.c
index fac6155f..3acee050 100644
--- a/src/json.c
+++ b/src/json.c
@@ -299,7 +299,7 @@ json_value * json_parse_ex (json_settings * settings,
          if (flags & flag_string)
          {
             if (!b)
-            {  sprintf (error, "Unexpected EOF in string (at %u:%u)", line_and_col);
+            {  snprintf (error, sizeof(error), "Unexpected EOF in string (at %u:%u)", line_and_col);
                goto e_failed;
             }
 
@@ -325,7 +325,7 @@ json_value * json_parse_ex (json_settings * settings,
                         (uc_b3 = hex_value (*++ state.ptr)) == 0xFF ||
                         (uc_b4 = hex_value (*++ state.ptr)) == 0xFF)
                     {
-                        sprintf (error, "Invalid character value `%c` (at %u:%u)", b, line_and_col);
+                        snprintf (error, sizeof(error), "Invalid character value `%c` (at %u:%u)", b, line_and_col);
                         goto e_failed;
                     }
 
@@ -342,7 +342,7 @@ json_value * json_parse_ex (json_settings * settings,
                             (uc_b3 = hex_value (*++ state.ptr)) == 0xFF ||
                             (uc_b4 = hex_value (*++ state.ptr)) == 0xFF)
                         {
-                            sprintf (error, "Invalid character value `%c` (at %u:%u)", b, line_and_col);
+                            snprintf (error, sizeof(error), "Invalid character value `%c` (at %u:%u)", b, line_and_col);
                             goto e_failed;
                         }
 
@@ -472,7 +472,7 @@ json_value * json_parse_ex (json_settings * settings,
                if (flags & flag_block_comment)
                {
                   if (!b)
-                  {  sprintf (error, "%u:%u: Unexpected EOF in block comment", line_and_col);
+                  {  snprintf (error, sizeof(error), "%u:%u: Unexpected EOF in block comment", line_and_col);
                      goto e_failed;
                   }
 
@@ -488,12 +488,12 @@ json_value * json_parse_ex (json_settings * settings,
             else if (b == '/')
             {
                if (! (flags & (flag_seek_value | flag_done)) && top->type != json_object)
-               {  sprintf (error, "%u:%u: Comment not allowed here", line_and_col);
+               {  snprintf (error, sizeof(error), "%u:%u: Comment not allowed here", line_and_col);
                   goto e_failed;
                }
 
                if (++ state.ptr == end)
-               {  sprintf (error, "%u:%u: EOF unexpected", line_and_col);
+               {  snprintf (error, sizeof(error), "%u:%u: EOF unexpected", line_and_col);
                   goto e_failed;
                }
 
@@ -508,7 +508,7 @@ json_value * json_parse_ex (json_settings * settings,
                      continue;
 
                   default:
-                     sprintf (error, "%u:%u: Unexpected `%c` in comment opening sequence", line_and_col, b);
+                     snprintf (error, sizeof(error), "%u:%u: Unexpected `%c` in comment opening sequence", line_and_col, b);
                      goto e_failed;
                };
             }
@@ -526,7 +526,7 @@ json_value * json_parse_ex (json_settings * settings,
 
                default:
 
-                  sprintf (error, "%u:%u: Trailing garbage: `%c`",
+                  snprintf (error, sizeof(error), "%u:%u: Trailing garbage: `%c`",
                            state.cur_line, state.cur_col, b);
 
                   goto e_failed;
@@ -545,7 +545,7 @@ json_value * json_parse_ex (json_settings * settings,
                   if (top && top->type == json_array)
                      flags = (flags & ~ (flag_need_comma | flag_seek_value)) | flag_next;
                   else
-                  {  sprintf (error, "%u:%u: Unexpected ]", line_and_col);
+                  {  snprintf (error, sizeof(error), "%u:%u: Unexpected ]", line_and_col);
                      goto e_failed;
                   }
 
@@ -561,7 +561,7 @@ json_value * json_parse_ex (json_settings * settings,
                      }
                      else
                      {
-                        sprintf (error, "%u:%u: Expected , before %c",
+                        snprintf (error, sizeof(error), "%u:%u: Expected , before %c",
                                  state.cur_line, state.cur_col, b);
 
                         goto e_failed;
@@ -576,7 +576,7 @@ json_value * json_parse_ex (json_settings * settings,
                      }
                      else
                      {
-                        sprintf (error, "%u:%u: Expected : before %c",
+                        snprintf (error, sizeof(error), "%u:%u: Expected : before %c",
                                  state.cur_line, state.cur_col, b);
 
                         goto e_failed;
@@ -702,7 +702,7 @@ json_value * json_parse_ex (json_settings * settings,
                            continue;
                         }
                         else
-                        {  sprintf (error, "%u:%u: Unexpected %c when seeking value", line_and_col, b);
+                        {  snprintf (error, sizeof(error), "%u:%u: Unexpected %c when seeking value", line_and_col, b);
                            goto e_failed;
                         }
                   };
@@ -722,7 +722,7 @@ json_value * json_parse_ex (json_settings * settings,
                   case '"':
 
                      if (flags & flag_need_comma)
-                     {  sprintf (error, "%u:%u: Expected , before \"", line_and_col);
+                     {  snprintf (error, sizeof(error), "%u:%u: Expected , before \"", line_and_col);
                         goto e_failed;
                      }
 
@@ -747,7 +747,7 @@ json_value * json_parse_ex (json_settings * settings,
                      }
                      /* FALLTHROUGH */
                   default:
-                     sprintf (error, "%u:%u: Unexpected `%c` in object", line_and_col, b);
+                     snprintf (error, sizeof(error), "%u:%u: Unexpected `%c` in object", line_and_col, b);
                      goto e_failed;
                };
 
@@ -765,7 +765,7 @@ json_value * json_parse_ex (json_settings * settings,
                      if (! (flags & flag_num_e))
                      {
                         if (flags & flag_num_zero)
-                        {  sprintf (error, "%u:%u: Unexpected `0` before `%c`", line_and_col, b);
+                        {  snprintf (error, sizeof(error), "%u:%u: Unexpected `0` before `%c`", line_and_col, b);
                            goto e_failed;
                         }
 
@@ -814,7 +814,7 @@ json_value * json_parse_ex (json_settings * settings,
                else if (b == '.' && top->type == json_integer)
                {
                   if (!num_digits)
-                  {  sprintf (error, "%u:%u: Expected digit before `.`", line_and_col);
+                  {  snprintf (error, sizeof(error), "%u:%u: Expected digit before `.`", line_and_col);
                      goto e_failed;
                   }
 
@@ -831,7 +831,7 @@ json_value * json_parse_ex (json_settings * settings,
                   if (top->type == json_double)
                   {
                      if (!num_digits)
-                     {  sprintf (error, "%u:%u: Expected digit after `.`", line_and_col);
+                     {  snprintf (error, sizeof(error), "%u:%u: Expected digit after `.`", line_and_col);
                         goto e_failed;
                      }
 
@@ -857,7 +857,7 @@ json_value * json_parse_ex (json_settings * settings,
                else
                {
                   if (!num_digits)
-                  {  sprintf (error, "%u:%u: Expected digit after `e`", line_and_col);
+                  {  snprintf (error, sizeof(error), "%u:%u: Expected digit after `e`", line_and_col);
                      goto e_failed;
                   }
 
@@ -942,7 +942,7 @@ json_value * json_parse_ex (json_settings * settings,
 
 e_unknown_value:
 
-   sprintf (error, "%u:%u: Unknown value", line_and_col);
+   snprintf (error, sizeof(error), "%u:%u: Unknown value", line_and_col);
    goto e_failed;
 
 e_alloc_failure:
@@ -952,7 +952,7 @@ e_alloc_failure:
 
 e_overflow:
 
-   sprintf (error, "%u:%u: Too long (caught overflow)", line_and_col);
+   snprintf (error, sizeof(error), "%u:%u: Too long (caught overflow)", line_and_col);
    goto e_failed;
 
 e_failed:
diff --git a/src/omit.c b/src/omit.c
index 1f5915f4..ce2755fc 100644
--- a/src/omit.c
+++ b/src/omit.c
@@ -218,7 +218,7 @@ int IsOmitted(int dse, int localomit, char const *omitfunc, int *omit)
         Value v;
 
         FromDSE(dse, &y, &m, &d);
-        sprintf(expr, "%s('%04d-%02d-%02d')",
+        snprintf(expr, sizeof(expr), "%s('%04d-%02d-%02d')",
                 omitfunc, y, m+1, d);
         s = expr;
         r = EvalExpr(&s, &v, NULL);
diff --git a/src/queue.c b/src/queue.c
index 132aa37b..be46b0ff 100644
--- a/src/queue.c
+++ b/src/queue.c
@@ -702,7 +702,7 @@ static int CalculateNextTimeUsingSched(QueuedRem *q)
                                      to be a security hole!                */
     while(1) {
         char exprBuf[VAR_NAME_LEN+32];
-        sprintf(exprBuf, "%s(%d)", q->sched, q->ntrig);
+        snprintf(exprBuf, sizeof(exprBuf), "%s(%d)", q->sched, q->ntrig);
         s = exprBuf;
         r = EvalExpr(&s, &v, NULL);
         if (r) {
diff --git a/src/rem2ps.c b/src/rem2ps.c
index 57f42f53..1033a6e4 100644
--- a/src/rem2ps.c
+++ b/src/rem2ps.c
@@ -1222,7 +1222,7 @@ int DoQueuedPs(void)
                 if (moonsize < 0) {
                     size = "DaySize 2 div";
                 } else {
-                    sprintf(buffer, "%d", moonsize);
+                    snprintf(buffer, sizeof(buffer), "%d", moonsize);
                     size = buffer;
                 }
 
@@ -1235,7 +1235,7 @@ int DoQueuedPs(void)
                         if (fontsize < 0) {
                             fsize = "EntrySize";
                         } else {
-                            sprintf(fbuffer, "%d", fontsize);
+                            snprintf(fbuffer, sizeof(fbuffer), "%d", fontsize);
                             fsize = fbuffer;
                         }
                         printf("/EntryFont findfont %s scalefont setfont (",
@@ -1273,7 +1273,7 @@ int DoQueuedPs(void)
                     if (fontsize < 0) {
                         fsize = "EntrySize";
                     } else {
-                        sprintf(fbuffer, "%d", fontsize);
+                        snprintf(fbuffer, sizeof(fbuffer), "%d", fontsize);
                         fsize = fbuffer;
                     }
                     printf("/EntryFont findfont %s scalefont setfont (",
diff --git a/src/sort.c b/src/sort.c
index 88fded2f..4bccc454 100644
--- a/src/sort.c
+++ b/src/sort.c
@@ -183,7 +183,7 @@ static void IssueSortBanner(int dse)
     if (UserFuncExists("sortbanner") != 1) return;
 
     FromDSE(dse, &y, &m, &d);
-    sprintf(BanExpr, "sortbanner('%04d/%02d/%02d')", y, m+1, d);   
+    snprintf(BanExpr, sizeof(BanExpr), "sortbanner('%04d/%02d/%02d')", y, m+1, d);   
     y = EvalExpr(&s, &v, NULL);
     if (y) return;
     if (DoCoerce(STR_TYPE, &v)) return;