diff --git a/lib/bufq.c b/lib/bufq.c
index 8783619eed..9919707b4c 100644
--- a/lib/bufq.c
+++ b/lib/bufq.c
@@ -174,6 +174,12 @@ static CURLcode bufcp_take(struct bufc_pool *pool,
     return CURLE_OK;
   }
 
+  /* Check for integer overflow before allocation */
+  if(pool->chunk_size > SIZE_MAX - sizeof(*chunk)) {
+    *pchunk = NULL;
+    return CURLE_OUT_OF_MEMORY;
+  }
+
   chunk = calloc(1, sizeof(*chunk) + pool->chunk_size);
   if(!chunk) {
     *pchunk = NULL;
@@ -302,6 +308,11 @@ static struct buf_chunk *get_spare(struct bufq *q)
     return chunk;
   }
   else {
+    /* Check for integer overflow before allocation */
+    if(q->chunk_size > SIZE_MAX - sizeof(*chunk)) {
+      return NULL;
+    }
+
     chunk = calloc(1, sizeof(*chunk) + q->chunk_size);
     if(!chunk)
       return NULL;