diff --git a/src/backend/port/dynloader/freebsd.c b/src/backend/port/dynloader/freebsd.c
index 0f2ec854a39344b70e357a7fea305c2cfb8b05cf..874eefce36a9cb3ea1b1494b0587f0a067a79b9f 100644
--- a/src/backend/port/dynloader/freebsd.c
+++ b/src/backend/port/dynloader/freebsd.c
@@ -63,13 +63,15 @@ void *
 BSD44_derived_dlopen(const char *file, int num)
 {
 #if defined(__mips__)
-	sprintf(error_message, "dlopen (%s) not supported", file);
+	snprintf(error_message, sizeof(error_message),
+			 "dlopen (%s) not supported", file);
 	return NULL;
 #else
 	void	   *vp;
 
 	if ((vp = dlopen((char *) file, num)) == (void *) NULL)
-		sprintf(error_message, "dlopen '%s' failed. (%s)", file, dlerror());
+		snprintf(error_message, sizeof(error_message),
+				 "dlopen '%s' failed. (%s)", file, dlerror());
 	return vp;
 #endif
 }
@@ -78,7 +80,8 @@ void *
 BSD44_derived_dlsym(void *handle, const char *name)
 {
 #if defined(__mips__)
-	sprintf(error_message, "dlsym (%s) failed", name);
+	snprintf(error_message, sizeof(error_message),
+			 "dlsym (%s) failed", name);
 	return NULL;
 #else
 	void	   *vp;
@@ -88,12 +91,13 @@ BSD44_derived_dlsym(void *handle, const char *name)
 
 	if (*name != '_')
 	{
-		sprintf(buf, "_%s", name);
+		snprintf(buf, sizeof(buf), "_%s", name);
 		name = buf;
 	}
 #endif
 	if ((vp = dlsym(handle, (char *) name)) == (void *) NULL)
-		sprintf(error_message, "dlsym (%s) failed", name);
+		snprintf(error_message, sizeof(error_message),
+				 "dlsym (%s) failed", name);
 	return vp;
 #endif
 }
diff --git a/src/backend/port/dynloader/netbsd.c b/src/backend/port/dynloader/netbsd.c
index 881b9711c1c8a2964475c5395e5dcc0d9fc842f1..26a4ec72c95c3658684587659599717d6e0067b4 100644
--- a/src/backend/port/dynloader/netbsd.c
+++ b/src/backend/port/dynloader/netbsd.c
@@ -63,13 +63,15 @@ void *
 BSD44_derived_dlopen(const char *file, int num)
 {
 #if defined(__mips__)
-	sprintf(error_message, "dlopen (%s) not supported", file);
+	snprintf(error_message, sizeof(error_message),
+			 "dlopen (%s) not supported", file);
 	return NULL;
 #else
 	void	   *vp;
 
 	if ((vp = dlopen((char *) file, num)) == (void *) NULL)
-		sprintf(error_message, "dlopen (%s) failed", file);
+		snprintf(error_message, sizeof(error_message),
+				 "dlopen (%s) failed", file);
 	return vp;
 #endif
 }
@@ -78,7 +80,8 @@ void *
 BSD44_derived_dlsym(void *handle, const char *name)
 {
 #if defined(__mips__)
-	sprintf(error_message, "dlsym (%s) failed", name);
+	snprintf(error_message, sizeof(error_message),
+			 "dlsym (%s) failed", name);
 	return NULL;
 #elif defined(__ELF__)
 	return dlsym(handle, name);
@@ -88,11 +91,12 @@ BSD44_derived_dlsym(void *handle, const char *name)
 
 	if (*name != '_')
 	{
-		sprintf(buf, "_%s", name);
+		snprintf(buf, sizeof(buf), "_%s", name);
 		name = buf;
 	}
 	if ((vp = dlsym(handle, (char *) name)) == (void *) NULL)
-		sprintf(error_message, "dlsym (%s) failed", name);
+		snprintf(error_message, sizeof(error_message),
+				 "dlsym (%s) failed", name);
 	return vp;
 #endif
 }
diff --git a/src/backend/port/dynloader/nextstep.c b/src/backend/port/dynloader/nextstep.c
index 98cf5c2f7812a1cf91c6800cd807f709cfdaf9d6..c7339636073e276584b18e46a5d32ed1b61acbd7 100644
--- a/src/backend/port/dynloader/nextstep.c
+++ b/src/backend/port/dynloader/nextstep.c
@@ -67,7 +67,7 @@ next_dlsym(void *handle, char *symbol)
 	char		symbuf[1024];
 	unsigned long symref = 0;
 
-	sprintf(symbuf, "_%s", symbol);
+	snprintf(symbuf, sizeof(symbuf), "_%s", symbol);
 	if (!rld_lookup(errorStream, symbuf, &symref))
 		TransferError(errorStream);
 	CloseError(errorStream);
diff --git a/src/backend/port/dynloader/openbsd.c b/src/backend/port/dynloader/openbsd.c
index 881b9711c1c8a2964475c5395e5dcc0d9fc842f1..26a4ec72c95c3658684587659599717d6e0067b4 100644
--- a/src/backend/port/dynloader/openbsd.c
+++ b/src/backend/port/dynloader/openbsd.c
@@ -63,13 +63,15 @@ void *
 BSD44_derived_dlopen(const char *file, int num)
 {
 #if defined(__mips__)
-	sprintf(error_message, "dlopen (%s) not supported", file);
+	snprintf(error_message, sizeof(error_message),
+			 "dlopen (%s) not supported", file);
 	return NULL;
 #else
 	void	   *vp;
 
 	if ((vp = dlopen((char *) file, num)) == (void *) NULL)
-		sprintf(error_message, "dlopen (%s) failed", file);
+		snprintf(error_message, sizeof(error_message),
+				 "dlopen (%s) failed", file);
 	return vp;
 #endif
 }
@@ -78,7 +80,8 @@ void *
 BSD44_derived_dlsym(void *handle, const char *name)
 {
 #if defined(__mips__)
-	sprintf(error_message, "dlsym (%s) failed", name);
+	snprintf(error_message, sizeof(error_message),
+			 "dlsym (%s) failed", name);
 	return NULL;
 #elif defined(__ELF__)
 	return dlsym(handle, name);
@@ -88,11 +91,12 @@ BSD44_derived_dlsym(void *handle, const char *name)
 
 	if (*name != '_')
 	{
-		sprintf(buf, "_%s", name);
+		snprintf(buf, sizeof(buf), "_%s", name);
 		name = buf;
 	}
 	if ((vp = dlsym(handle, (char *) name)) == (void *) NULL)
-		sprintf(error_message, "dlsym (%s) failed", name);
+		snprintf(error_message, sizeof(error_message),
+				 "dlsym (%s) failed", name);
 	return vp;
 #endif
 }