diff --git a/src/H5Cimage.c b/src/H5Cimage.c
index d626640dbdd..ac8c2fa0690 100644
--- a/src/H5Cimage.c
+++ b/src/H5Cimage.c
@@ -1287,6 +1287,11 @@ H5C__decode_cache_image_header(const H5F_t *f, H5C_t *cache_ptr, const uint8_t *
     /* Point to buffer to decode */
     p = *buf;
 
+    /* Ensure buffer has enough data for signature comparison */
+    if ((size_t)(*buf + H5C__MDCI_BLOCK_SIGNATURE_LEN - p) > cache_ptr->image_len)
+        HGOTO_ERROR(H5E_CACHE, H5E_OVERFLOW, FAIL, "Insufficient buffer size for signature");
+
+
     /* Check signature */
     if (memcmp(p, H5C__MDCI_BLOCK_SIGNATURE, (size_t)H5C__MDCI_BLOCK_SIGNATURE_LEN) != 0)
         HGOTO_ERROR(H5E_CACHE, H5E_BADVALUE, FAIL, "Bad metadata cache image header signature");