CVE-2023-35941: Envoyproxy Envoy

Critical severity, CVSS 9.8. EPSS: 0.8% chance of exploitation in the next 30 days.

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12, a malicious client is able to construct credentials with permanent validity in some specific scenarios. This is caused by the some rare scenarios in which HMAC payload can be always valid in OAuth2 filter's check. Versions 1.27.0, 1.26.4, 1.25.9, 1.24.10, and 1.23.12 have a fix for this issue. As a workaround, avoid wildcards/prefix domain wildcards in the host's domain configuration.

Affected products

• Envoyproxy Envoy: from 1.23.0, before 1.23.12 (fixed in 1.23.12); from 1.24.0, before 1.24.10 (fixed in 1.24.10); from 1.25.0, before 1.25.9 (fixed in 1.25.9); from 1.26.0, before 1.26.4 (fixed in 1.26.4)

Published 2023-07-25. Last modified 2026-06-17.