8.2

CVE-2026-26308

Exploit

Envoy has an RBAC Header Validation Bypass via Multi-Value Header Concatenation

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 present for the same header name. Instead of validating each header value individually, Envoy concatenates all values into a single comma-separated string. This behavior allows attackers to bypass RBAC policies—specifically "Deny" rules—by sending duplicate headers, effectively obscuring the malicious value from exact-match mechanisms. This vulnerability is fixed in 1.37.1, 1.36.5, 1.35.8, and 1.34.13.
Daten sind bereitgestellt durch National Vulnerability Database (NVD)
Envoyproxy ≫ Envoy Version < 1.34.13
Envoyproxy ≫ Envoy Version >= 1.35.0 < 1.35.8
Envoyproxy ≫ Envoy Version >= 1.36.0 < 1.36.5
Envoyproxy ≫ Envoy Version 1.37.0
VulnDex Vulnerability Enrichment
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Zu dieser CVE wurde keine Warnung gefunden.
EPSS Metriken
Typ Quelle Score Percentile
EPSS FIRST.org 0.29% 0.207
CVSS Metriken
Quelle Base Score Exploit Score Impact Score Vector String
NIST 8.2 3.9 4.2
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
security-advisories@github.com 7.5 2.2 4.7
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:L/A:N
CWE-863 Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

https://github.com/envoyproxy/envoy/security/advisories/GHSA-ghc4-35x6-crw5
Vendor Advisory
Exploit
Mitigation
https://github.com/envoyproxy/envoy/commit/b6ba0b2294b98484fb0ed8556897d1073cc27867
Patch