Vulnerability in Envoyproxy Envoy

CVE-2025-55162

Envoy is an open source L7 proxy and communication bus designed for large modern service oriented architectures. In versions below 1.32.10 and 1.33.0 through 1.33.6, 1.34.0 through 1.34.4 and 1.35.0, insufficient Session Expiration in the Envoy OAuth2 filter leads to failed logout operations. When configured with __Secure- or __Host- prefixed cookie names, the filter fails to append the required Secure attribute to the Set-Cookie header during deletion. Modern browsers ignore this invalid request, causing the session cookie to persist. This allows a user to remain logged in after they believe they have logged out, creating a session hijacking risk on shared computers. The current implementation iterates through the configured cookie names to generate deletion headers but does not check for these prefixes. This failure to properly construct the deletion header means the user's session cookies are never removed by the browser, leaving the session active and allowing the next user of the same browser to gain unauthorized access to the original user's account and data. This is fixed in versions 1.32.10, 1.33.7, 1.34.5 and 1.35.1.

EPSS: 0.003 (23.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:L/A:N.

Affected products

  • Envoyproxy Envoy — versions <= 1.32.0, < 1.32.10, >= 1.34.0, < 1.34.5, >= 1.33.0, < 1.33.7

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-55162?
CVE-2025-55162 is a medium-severity vulnerability in Envoyproxy Envoy, classified under Insufficient Session Expiration. CVSS score: 6.3/10. Published 2025-09-03.
How severe is CVE-2025-55162?
Medium severity. CVSS v3 base score is 6.3 out of 10.
Is CVE-2025-55162 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.