--- a/sys/net/zlib.c
+++ b/sys/net/zlib.c
@@ -785,9 +785,15 @@ uLong ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
     s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
     if (s == Z_NULL) return Z_MEM_ERROR;
     strm->state = (struct internal_state FAR *)s;
     s->strm = strm;
+    /*
+     * deflateEnd() gates every cleanup path on s->status; the consumer
+     * zalloc (kernel kmalloc without M_ZERO) does not zero it, and the
+     * normal assignment only happens in deflateReset() after all
+     * sub-allocations succeed.  An allocation failure before that makes
+     * deflateEnd() read uninitialized memory and leak every allocation.
+     */
+    s->status = INIT_STATE;
 
     s->noheader = noheader;