CVE-2025-62409: 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.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2025-62409?
CVE-2025-62409 has been classified with a severity that may lead to crashes in the TCP connection pool under specific conditions.
How do I fix CVE-2025-62409?
To fix CVE-2025-62409, upgrade to Envoy version 1.36.1 or later, or to the latest respective versions above 1.35.5, 1.34.9, and 1.33.10.
What causes CVE-2025-62409?
CVE-2025-62409 is caused by issues in flow control management that can lead to crashes when managing large requests and responses.
Which versions of Envoy are affected by CVE-2025-62409?
The affected versions of Envoy include all versions prior to 1.36.1, 1.35.5, 1.34.9, and 1.33.10.
What impact does CVE-2025-62409 have on my systems?
CVE-2025-62409 can disrupt service by causing crashes of the TCP connection pool, potentially impacting application availability.