diff --git a/src/fish_tests.cpp b/src/fish_tests.cpp
index 7a20303a8..96be9af0e 100644
--- a/src/fish_tests.cpp
+++ b/src/fish_tests.cpp
@@ -478,7 +478,7 @@ static void test_format() {
     for (int j = -129; j <= 129; j++) {
         char buff1[128], buff2[128];
         format_long_safe(buff1, j);
-        sprintf(buff2, "%d", j);
+        snprintf(buff2, 128, "%d", j);
         do_test(!std::strcmp(buff1, buff2));
 
         wchar_t wbuf1[128], wbuf2[128];
@@ -490,7 +490,7 @@ static void test_format() {
     long q = LONG_MIN;
     char buff1[128], buff2[128];
     format_long_safe(buff1, q);
-    sprintf(buff2, "%ld", q);
+    snprintf(buff2, 128, "%ld", q);
     do_test(!std::strcmp(buff1, buff2));
 }
 
diff --git a/src/proc.cpp b/src/proc.cpp
index ff0baa1e2..1edc6d75e 100644
--- a/src/proc.cpp
+++ b/src/proc.cpp
@@ -132,7 +132,7 @@ bool job_t::signal(int signal) {
     if (auto pgid = group->get_pgid()) {
         if (killpg(*pgid, signal) == -1) {
             char buffer[512];
-            sprintf(buffer, "killpg(%d, %s)", *pgid, strsignal(signal));
+            snprintf(buffer, 512, "killpg(%d, %s)", *pgid, strsignal(signal));
             wperror(str2wcstring(buffer).c_str());
             return false;
         }