Flow Control Management Vulnerability in Envoy Proxy by Envoy
CVE-2025-62409

6.6MEDIUM

Key Information:

Vendor

Envoyproxy

Status
Envoy
Vendor
CVE Published:
16 October 2025

What is CVE-2025-62409?

The Envoy Proxy, a cloud-native edge and service proxy, has a vulnerability related to flow control management that can lead to TCP connection pool crashes. This issue arises when a connection is closing while upstream data continues to flow, causing a null reference in the buffer watermark callback. Affected scenarios include TCP proxy and HTTP/1 & 2 mixed usage with ALPN. The issue is addressed in versions 1.36.1, 1.35.5, 1.34.9, and 1.33.10.

Affected Version(s)

envoy >= 1.36.0, < 1.36.1 < 1.36.0, 1.36.1

envoy >= 1.35.0, < 1.35.5 < 1.35.0, 1.35.5

envoy >= 1.34.0, < 1.34.9 < 1.34.0, 1.34.9

References

https://github.com/envoyproxy/envoy/security/advisories/G...
x_refsource_CONFIRM

CVSS V4

Score:
6.6
Severity:
MEDIUM
Confidentiality:
None
Integrity:
None
Availability:
High
Attack Vector:
Network
Attack Complexity:
Low
Attack Required:
None
Privileges Required:
Undefined
User Interaction:
None

Timeline

  • Vulnerability published

  • Vulnerability Reserved

JSON
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CVE-2025-62409 : Flow Control Management Vulnerability in Envoy Proxy by Envoy