envoyproxy Envoy up to 1.36.9/1.37.5/1.38.3/1.39.0 RBAC FullMatch input validation

Summaryinfo

A vulnerability identified as problematic has been detected in envoyproxy Envoy up to 1.36.9/1.37.5/1.38.3/1.39.0. This vulnerability affects the function FullMatch of the component RBAC. This manipulation causes input validation. This vulnerability is registered as CVE-2026-73552. Remote exploitation of the attack is possible. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability has been found in envoyproxy Envoy up to 1.36.9/1.37.5/1.38.3/1.39.0 and classified as problematic. Affected by this vulnerability is the function FullMatch of the component RBAC. The manipulation with an unknown input leads to a input validation vulnerability. The CWE definition for the vulnerability is CWE-20. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly. As an impact it is known to affect confidentiality. The summary by CVE is:

Envoy is an open source edge and service proxy designed for cloud-native applications. Prior to 1.36.10, 1.37.6, 1.38.4, and 1.39.1, Envoy HTTP RBAC accepts RFC-valid opaque header bytes but evaluates safe_regex values with RE2's UTF-8 subject semantics. A downstream client can preserve a prohibited marker and add an unrelated obs-text octet, causing RE2::FullMatch to return false and a negative RBAC policy to treat the invalid subject as an ordinary no-match. A byte-oriented route matcher can still observe the marker, allowing the request to reach a route intended to be denied. The relevant scope boundary is that plain positive ALLOW regexes normally fail closed, and exact, prefix, suffix, and contains matchers are not shown to have this subject-domain failure. This issue is fixed in versions 1.36.10, 1.37.6, 1.38.4, and 1.39.1.

It is possible to read the advisory at github.com. This vulnerability is known as CVE-2026-73552 since 08/12/2026. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. Technical details of the vulnerability are known, but there is no available exploit.

Upgrading to version 1.36.10, 1.37.6, 1.38.4 or 1.39.1 eliminates this vulnerability.

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Productinfo

Type

• Firewall Software

Vendor

• envoyproxy

Name

• Envoy

Version

• 1.0
• 1.1
• 1.2
• 1.3
• 1.4
• 1.5
• 1.6
• 1.7
• 1.8
• 1.9
• 1.10
• 1.11
• 1.12
• 1.13
• 1.14
• 1.15
• 1.16
• 1.17
• 1.18
• 1.19
• 1.20
• 1.21
• 1.22
• 1.23
• 1.24
• 1.25
• 1.26
• 1.27
• 1.28
• 1.29
• 1.30
• 1.31
• 1.32
• 1.33
• 1.34
• 1.35
• 1.36
• 1.36.0
• 1.36.1
• 1.36.2
• 1.36.3
• 1.36.4
• 1.36.5
• 1.36.6
• 1.36.7
• 1.36.8
• 1.36.9
• 1.37
• 1.37.0
• 1.37.1
• 1.37.2
• 1.37.3
• 1.37.4
• 1.37.5
• 1.38
• 1.38.0
• 1.38.1
• 1.38.2
• 1.38.3
• 1.39.0

License

• free

Website

• Product: https://github.com/envoyproxy/envoy/

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