Envoy is a cloud-native, open source edge and service proxy. Prior to 1.36.1, 1.35.5, 1.34.9, and 1.33.10, large requests and responses can potentially trigger TCP connection pool crashes due to flow control management in Envoy. It will happen when the connection is closing but upstream data is still coming, resulting in a buffer watermark callback nullptr reference. The vulnerability impacts TCP proxy and HTTP 1 & 2 mixed use cases based on ALPN. This vulnerability is fixed in 1.36.1, 1.35.5, 1.34.9, and 1.33.10.
Fix
Patch, vendor advisory and mitigation references on NVD 2
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-pq33-4jxh-hgm3 Vendor Advisory
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-pq33-4jxh-hgm3 Vendor Advisory
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 6.6 · envoyproxyNVD modified 2026-10-09 10:10
Affected (CPE criteria) 2
cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:*cpe:2.3:a:envoyproxy:envoy:1.36.0:*:*:*:*:*:*:*