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.
Metrics
Affected Vendors & Products
References
History
Wed, 11 Mar 2026 16:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:2.3:a:envoyproxy:envoy:*:*:*:*:*:*:*:* cpe:2.3:a:envoyproxy:envoy:1.37.0:*:*:*:*:*:*:* |
Wed, 11 Mar 2026 12:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Envoyproxy
Envoyproxy envoy |
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| Vendors & Products |
Envoyproxy
Envoyproxy envoy |
Tue, 10 Mar 2026 21:15:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
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Tue, 10 Mar 2026 19:30:00 +0000
| Type | Values Removed | Values Added |
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| Description | 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. | |
| Title | Envoy has an RBAC Header Validation Bypass via Multi-Value Header Concatenation | |
| Weaknesses | CWE-863 | |
| References |
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| Metrics |
cvssV3_1
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Status: PUBLISHED
Assigner: GitHub_M
Published: 2026-03-10T19:01:28.062Z
Updated: 2026-03-10T20:12:40.604Z
Reserved: 2026-02-13T16:27:51.804Z
Link: CVE-2026-26308
Updated: 2026-03-10T20:11:58.525Z
Status : Analyzed
Published: 2026-03-10T20:16:35.707
Modified: 2026-03-11T16:23:23.090
Link: CVE-2026-26308
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