CVE-2026-47692

Envoy: PROXY Protocol v2 header generator emits "skipped" TLVs, causing 65 KB attacker-controlled spillover into the upstream application stream

State: Published
Severity: 4.8 Medium
Published: Jun 26, 2026
Updated: Jun 26, 2026
Reserved: May 19, 2026

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Description

Envoy is an open source edge and service proxy designed for cloud-native applications. From 1.34.0 until 1.35.13, 1.36.9, 1.37.5, and 1.38.3, PROXY Protocol v2 header generator emits TLVs beyond the maximum length of 65535 bytes, causing a mismatch between bytes written and the length field in the header. This can result in smuggled bytes on the upstream request. This vulnerability is fixed in 1.35.13, 1.36.9, 1.37.5, and 1.38.3.

Scores

CVSS	Score	Vector	Source
3.1	4.8 Medium	CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:C/C:N/I:L/A:L	GitHub_M

Weaknesses

CWE-130 Improper Handling of Length Parameter Inconsistency

Affected Products

Product	Versions
envoyenvoyproxy	>= 1.38.0, < 1.38.3Affected >= 1.37.0, < 1.37.5Affected >= 1.36.0, < 1.36.9Affected >= 1.34.0, < 1.35.13Affected

References

https://github.com/envoyproxy/envoy/security/advisories/GHSA-wh36-hm39-mm3r

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