Vulnerability from bitnami_vulndb
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.
{
"affected": [
{
"package": {
"ecosystem": "Bitnami",
"name": "envoy",
"purl": "pkg:bitnami/envoy"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"fixed": "1.34.13"
},
{
"introduced": "1.35.0"
},
{
"fixed": "1.35.9"
},
{
"introduced": "1.36.0"
},
{
"fixed": "1.36.5"
},
{
"introduced": "1.37.0"
},
{
"fixed": "1.37.1"
}
],
"type": "SEMVER"
}
],
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N",
"type": "CVSS_V3"
}
]
}
],
"aliases": [
"CVE-2026-26308"
],
"database_specific": {
"cpes": [
"cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:go:*:*"
],
"severity": "High"
},
"details": "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\u2014specifically \"Deny\" rules\u2014by 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.",
"id": "BIT-envoy-2026-26308",
"modified": "2026-09-08T08:34:36.952Z",
"published": "2026-03-12T08:39:41.078Z",
"references": [
{
"type": "FIX",
"url": "https://github.com/envoyproxy/envoy/commit/b6ba0b2294b98484fb0ed8556897d1073cc27867"
},
{
"type": "ADVISORY",
"url": "https://github.com/envoyproxy/envoy/security/advisories/GHSA-ghc4-35x6-crw5"
},
{
"type": "WEB",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-26308"
}
],
"schema_version": "1.6.2",
"summary": "Envoy has an RBAC Header Validation Bypass via Multi-Value Header Concatenation"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
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- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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