CVE-2026-73552Envoy: HTTP RBAC safe_regex can fail open on RFC-valid obs-text header values
Updated under an hour ago ()
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No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.5 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
- Weakness (CWE)
- CWE-20
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Analyzed
- Record last updated
- Sep 22, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
envoyproxy envoy envoyproxy:envoy (from the name) | before 1.36.10; from 1.37.0, < 1.37.6; from 1.38.0, < 1.38.4; from 1.39.0, < 1.39.1 | CNA record |
envoyproxy envoy envoyproxy:envoy | before 1.36.10; from 1.37.0 before 1.37.6; from 1.38.0 before 1.38.4; from 1.39.0 before 1.39.1 | NVD |
References
- https://github.com/envoyproxy/envoy/security/advisories/GHSA-23xh-2qxr-3xv8x-refsource-confirm, exploit, vendor-advisory
- https://github.com/envoyproxy/envoy/commit/5650cb9770d4420ec2bcbed8b90be06f564ecc07x-refsource-misc, patch
- https://github.com/envoyproxy/envoy/commit/7d1dee5dda66434d84437cc5c85153aa03955e26x-refsource-misc, patch
- https://github.com/envoyproxy/envoy/commit/c2b9a19dc081f03be6a9b4ca932673e5e7a33d18x-refsource-misc, patch
- https://github.com/envoyproxy/envoy/commit/f3726765f3a12ddc76dcb52c0b79bec3d95ced1cx-refsource-misc, patch
- https://github.com/envoyproxy/envoy/releases/tag/v1.36.10x-refsource-misc, release-notes
- https://github.com/envoyproxy/envoy/releases/tag/v1.37.6x-refsource-misc, release-notes
- https://github.com/envoyproxy/envoy/releases/tag/v1.38.4x-refsource-misc, release-notes
- https://github.com/envoyproxy/envoy/releases/tag/v1.39.1x-refsource-misc, release-notes
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.