diff --git a/src/zmalloc.c b/src/zmalloc.c
index 857baa8ac8..dc9d7cbc4e 100644
--- a/src/zmalloc.c
+++ b/src/zmalloc.c
@@ -59,14 +59,12 @@ void zlibc_free(void *ptr) {
 
 #ifdef HAVE_MALLOC_SIZE
 #define PREFIX_SIZE (0)
-#define ASSERT_NO_SIZE_OVERFLOW(sz)
 #else
 #if defined(__sun) || defined(__sparc) || defined(__sparc__)
 #define PREFIX_SIZE (sizeof(long long))
 #else
 #define PREFIX_SIZE (sizeof(size_t))
 #endif
-#define ASSERT_NO_SIZE_OVERFLOW(sz) assert((sz) + PREFIX_SIZE > (sz))
 #endif
 
 /* When using the libc allocator, use a minimum allocation size to match the
@@ -106,7 +104,8 @@ static void (*zmalloc_oom_handler)(size_t) = zmalloc_default_oom;
 /* Try allocating memory, and return NULL if failed.
  * '*usable' is set to the usable size if non NULL. */
 void *ztrymalloc_usable(size_t size, size_t *usable) {
-    ASSERT_NO_SIZE_OVERFLOW(size);
+    /* Possible overflow, return NULL, so that the caller can panic or handle a failed allocation. */
+    if (size >= SIZE_MAX/2) return NULL;
     void *ptr = malloc(MALLOC_MIN_SIZE(size)+PREFIX_SIZE);
 
     if (!ptr) return NULL;
@@ -149,7 +148,7 @@ void *zmalloc_usable(size_t size, size_t *usable) {
  * Currently implemented only for jemalloc. Used for online defragmentation. */
 #ifdef HAVE_DEFRAG
 void *zmalloc_no_tcache(size_t size) {
-    ASSERT_NO_SIZE_OVERFLOW(size);
+    if (size >= SIZE_MAX/2) zmalloc_oom_handler(size);
     void *ptr = mallocx(size+PREFIX_SIZE, MALLOCX_TCACHE_NONE);
     if (!ptr) zmalloc_oom_handler(size);
     update_zmalloc_stat_alloc(zmalloc_size(ptr));
@@ -166,7 +165,8 @@ void zfree_no_tcache(void *ptr) {
 /* Try allocating memory and zero it, and return NULL if failed.
  * '*usable' is set to the usable size if non NULL. */
 void *ztrycalloc_usable(size_t size, size_t *usable) {
-    ASSERT_NO_SIZE_OVERFLOW(size);
+    /* Possible overflow, return NULL, so that the caller can panic or handle a failed allocation. */
+    if (size >= SIZE_MAX/2) return NULL;
     void *ptr = calloc(1, MALLOC_MIN_SIZE(size)+PREFIX_SIZE);
     if (ptr == NULL) return NULL;
 
@@ -221,7 +221,6 @@ void *zcalloc_usable(size_t size, size_t *usable) {
 /* Try reallocating memory, and return NULL if failed.
  * '*usable' is set to the usable size if non NULL. */
 void *ztryrealloc_usable(void *ptr, size_t size, size_t *usable) {
-    ASSERT_NO_SIZE_OVERFLOW(size);
 #ifndef HAVE_MALLOC_SIZE
     void *realptr;
 #endif
@@ -238,6 +237,13 @@ void *ztryrealloc_usable(void *ptr, size_t size, size_t *usable) {
     if (ptr == NULL)
         return ztrymalloc_usable(size, usable);
 
+    /* Possible overflow, return NULL, so that the caller can panic or handle a failed allocation. */
+    if (size >= SIZE_MAX/2) {
+        zfree(ptr);
+        if (usable) *usable = 0;
+        return NULL;
+    }
+
 #ifdef HAVE_MALLOC_SIZE
     oldsize = zmalloc_size(ptr);
     newptr = realloc(ptr,size);
diff --git a/tests/integration/corrupt-dump.tcl b/tests/integration/corrupt-dump.tcl
index 1e54f26a1b..1b9be676b9 100644
--- a/tests/integration/corrupt-dump.tcl
+++ b/tests/integration/corrupt-dump.tcl
@@ -790,5 +790,16 @@ test {corrupt payload: fuzzer findings - streamLastValidID panic} {
     }
 }
 
+test {corrupt payload: fuzzer findings - valgrind fishy value warning} {
+    start_server [list overrides [list loglevel verbose use-exit-on-panic yes crash-memcheck-enabled no] ] {
+        r config set sanitize-dump-payload yes
+        r debug set-skip-checksum-validation 1
+        catch {r restore _key 0 "\x13\x01\x10\x00\x00\x01\x81\xCC\x07\xDC\xF2\x00\x00\x00\x00\x00\x00\x00\x00\x40\x42\x42\x00\x00\x00\x18\x00\x02\x01\x01\x01\x02\x01\x84\x69\x74\x65\x6D\x05\x85\x76\x61\x6C\x75\x65\x06\x00\x01\x02\x01\x00\x01\x00\x01\x01\x01\x00\x01\x05\x01\x03\x01\x2C\x01\x00\x01\x01\x01\x82\x5F\x31\x03\x05\x01\x02\x01\x3C\x01\x00\x01\x01\x01\x02\x01\x05\x01\xFF\x02\xD0\x00\x00\x01\x81\xCC\x07\xDD\x2E\x00\x81\x00\x00\x01\x81\xCC\x07\xDC\xF2\x00\x81\x00\x00\x01\x81\xCC\x07\xDD\x1E\x00\x03\x01\x07\x6D\x79\x67\x72\x6F\x75\x70\x81\x00\x00\x01\x81\xCC\x07\xDD\x1E\x00\x02\x01\x00\x00\x01\x81\xCC\x07\xDD\x1E\x00\x00\x00\x00\x00\x00\x00\x00\x71\xDD\x07\xCC\x81\x01\x00\x00\x01\x01\x05\x41\x6C\x69\x63\x65\x58\xDD\x07\xCC\x81\x01\x00\x00\x01\x00\x00\x01\x81\xCC\x07\xDD\x1E\x00\x00\x00\x00\x00\x00\x00\x00\x0A\x00\x2F\xB0\xD1\x15\x0A\x97\x87\x6B"} err
+        assert_match "*Bad data format*" $err
+        r ping
+    }
+}
+
+
 } ;# tags