🛡️ CVE-2025-62409 — envoy

🟡 CVSS 5.0 — Medium ✅ No Known Exploit CWE-476 OSV
5.0
CVSS Score
0 Low4 Medium7 High9 Critical10

Description

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

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.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Weakness class

CVE-2025-62409 is classified as CWE-476: NULL Pointer Dereference. A pointer that can be null is used without a check, crashing the process.

Affected software

CVE-2025-62409 is recorded against 1 package.

  • envoy

Timeline and source

Published on 21 October 2025 and last revised on 17 June 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

github.com (Web)
nvd.nist.gov (Web)

Details

Severity MEDIUM
CVSS Score 5.0
CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE CWE-476
Public Exploit ✅ No
Source OSV
Published 2025-10-21
Updated 2026-08-12
Modified 2026-06-17
Fix URL N/A

Affected Packages

Software From version Fixed in
envoy — —

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