Potential fix for pull request finding

Co-authored-by: Copilot Autofix powered by AI <175728472+Copilot@users.noreply.github.com>

Author: mathieucarbou

src/WebRequest.cpp

@@ -562,7 +562,12 @@ bool AsyncWebServerRequest::_parseReqHeader() {
           bvlen--;
           // Reserve at most 70 chars — the RFC 2046 §5.1 maximum — rather than
           // the full (attacker-controlled) remaining suffix length.
-          _boundary.reserve(70);
+          if (!_boundary.reserve(70)) {
+            async_ws_log_e("Failed to allocate");
+            _parseState = PARSE_REQ_FAIL;
+            abort();
+            return true;
+          }
           bool closed = false;
           for (size_t i = 0; i < bvlen; ++i) {
             char c = bvdata[i];