CVE-2025-62409

Envoy allows large requests and responses to cause TCP connection pool crash

State: Published
Severity: 6.6 Medium
Published: Oct 16, 2025
Updated: Oct 16, 2025
Reserved: Oct 13, 2025

Description

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.

Scores

CVSS	Score	Vector	Source
4.0	6.6 Medium	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U	GitHub_M

Weaknesses

CWE-476 NULL Pointer Dereference

Affected Products

Product	Versions
envoyenvoyproxy	>= 1.36.0, < 1.36.1Affected >= 1.35.0, < 1.35.5Affected >= 1.34.0, < 1.34.9Affected < 1.33.10Affected

References

https://github.com/envoyproxy/envoy/security/advisories/GHSA-pq33-4jxh-hgm3

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