What is CVE-2026-26308?

CVE-2026-26308 is a high-severity vulnerability in Envoyproxy Envoy, classified under Incorrect Authorization. CVSS score: 7.5/10. Published 2026-03-10.

How severe is CVE-2026-26308?

High severity. CVSS v3 base score is 7.5 out of 10.

Auth bypass in Envoyproxy Envoy

CVE-2026-26308

Envoy is a high-performance edge/middle/service proxy. Prior to 1.37.1, 1.36.5, 1.35.8, and 1.34.13, the Envoy RBAC (Role-Based Access Control) filter contains a logic vulnerability in how it validates HTTP headers when multiple values are…

Vulnerability class: Broken Access Control

EPSS: 0.000 (0.1th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N.

Affected products

Envoyproxy Envoy — versions >= 1.37.0, < 1.37.1, >= 1.36.0, < 1.36.5, >= 1.35.0, < 1.35.9

Weakness classification (CWE)

CWE-863 — Incorrect Authorization

References

https://github.com/envoyproxy/envoy/security/advisories/GHSA-ghc4-35x6-crw5 (x_refsource_CONFIRM)
https://github.com/envoyproxy/envoy/commit/b6ba0b2294b98484fb0ed8556897d1073cc27867 (x_refsource_MISC)

Frequently asked questions

What is CVE-2026-26308?: CVE-2026-26308 is a high-severity vulnerability in Envoyproxy Envoy, classified under Incorrect Authorization. CVSS score: 7.5/10. Published 2026-03-10.
How severe is CVE-2026-26308?: High severity. CVSS v3 base score is 7.5 out of 10.