## MessagePack: Unbounded memory leak in msgpack C extension on strict_map_key validation failure

- 種別: advisory
- 重大度: high
- 関連技術: python
- CVE: CVE-2026-114613
- 公開日時: 2026-10-27T15:04:07.000Z
- 情報源: GitHub Advisory Database (https://github.com/advisories/GHSA-j586-36cw-2gc2)
- パーマリンク: https://vulnpulse.app/items/ghsa-ghsa-j586-36cw-2gc2

影響: pip:msgpack < 1.2.3 → 1.2.3
The msgpack-python C extension (msgpack._cmsgpack) leaks a decoded map value when deserialization rejects a key with strict_map_key=True (the default). Repeated malformed inputs can cause unbounded process memory growth and denial of service in applications that deserialize attacker-controlled MessagePack data. Both unpackb() and the streaming Unpacker API are affected. The pure-Python fallback does not exhibit this leak in the reported tests. The report measured approximately 4 MiB retained pe…