CVE-2025-62409

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.

How to fix CVE-2025-62409

To remediate CVE-2025-62409, upgrade the affected package to a fixed version below.

• —upgrade to 1.33.10 or later

Is CVE-2025-62409 being exploited?

Low — EPSS is 0.0%, meaning exploitation activity has not been observed at scale.

Affected packages (1)

• from 0, < 1.33.10, >= 1.34.0, < 1.34.9, >= 1.35.0, < 1.35.5, >= 1.36.0, < 1.36.1

CVSS scores

References (2)

• WEBgithub.com/envoyproxy/envoy/security/advisories/GHSA-pq33-4jxh-hgm3
• WEBnvd.nist.gov/vuln/detail/CVE-2025-62409