CVE-2026-26308
CVE.org · Published
- Record status
- Published
- Identifier year (not publication year)
- 2026
- Source publication
- Source updated
- Imported by cveboard
- Source snapshot
- cve_2026-10-24_midnight_baseline ·
CNA source text (English)
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.
Scoped product and version facts
Fix information unknown; no fixed version is derived here. Missing information does not prove that no fix exists.
Exploitation unknown; this catalogue does not assess exploitation.
envoy
- Vendor
- envoyproxy
- Product
- envoy
- Platforms
- Unknown
- Default status
Unknown
| Version (version) | Status (status) | Version scheme (versionType) | Exclusive end (lessThan) | Inclusive end (lessThanOrEqual) | Status changes (at → status) |
|---|---|---|---|---|---|
| >= 1.37.0, < 1.37.1 | affected | Unavailable | Unavailable | Unavailable | None listed |
| >= 1.36.0, < 1.36.5 | affected | Unavailable | Unavailable | Unavailable | None listed |
| >= 1.35.0, < 1.35.9 | affected | Unavailable | Unavailable | Unavailable | None listed |
| < 1.34.13 | affected | Unavailable | Unavailable | Unavailable | None listed |