CVE-2026-73552

high

Envoy is an open source edge and service proxy designed for cloud-native applications.

Vendor / product: Envoyproxy — envoy

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

7.5 (CVSS v3.1)

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

Severity source: NVD CVSS v3.1 (security-advisories@github.com)

Timeline (UTC)

Published: 2026-09-21 20:17

Modified: 2026-10-05 14:35

NVD status: Analyzed

Last synced 2 days ago

Verified against the source API 2026-10-27 06:54 UTC

Exploitation

Not listed in CISA KEV (as of last catalog sync)

Absence from KEV does not mean a CVE is not exploited. Exploitation status: unknown (no authoritative evidence in our sources).

Affected products

envoyproxy / envoy <1.36.10, ≥1.37.0 <1.37.6, ≥1.38.0 <1.38.4, ≥1.39.0 <1.39.1

Weakness classification (CWE)

CWE-20

Source: NVD / CISA. “NVD-CWE-Other” and “NVD-CWE-noinfo” mean NVD could not assign a specific weakness.

Mitigation & advisories

Vendor advisory: https://github.com/envoyproxy/envoy/security/advisories/GHSA-23xh-2qxr-3xv8

Patch / mitigation: https://github.com/envoyproxy/envoy/commit/5650cb9770d4420ec2bcbed8b90be06f564ecc07

Patch / mitigation: https://github.com/envoyproxy/envoy/commit/7d1dee5dda66434d84437cc5c85153aa03955e26

Patch / mitigation: https://github.com/envoyproxy/envoy/commit/c2b9a19dc081f03be6a9b4ca932673e5e7a33d18

Patch / mitigation: https://github.com/envoyproxy/envoy/commit/f3726765f3a12ddc76dcb52c0b79bec3d95ced1c

References

https://github.com/envoyproxy/envoy/commit/5650cb9770d4420ec2bcbed8b90be06f564ecc07 security-advisories@github.com
https://github.com/envoyproxy/envoy/commit/7d1dee5dda66434d84437cc5c85153aa03955e26 security-advisories@github.com
https://github.com/envoyproxy/envoy/commit/c2b9a19dc081f03be6a9b4ca932673e5e7a33d18 security-advisories@github.com
https://github.com/envoyproxy/envoy/commit/f3726765f3a12ddc76dcb52c0b79bec3d95ced1c security-advisories@github.com
https://github.com/envoyproxy/envoy/releases/tag/v1.36.10 security-advisories@github.com
https://github.com/envoyproxy/envoy/releases/tag/v1.37.6 security-advisories@github.com
https://github.com/envoyproxy/envoy/releases/tag/v1.38.4 security-advisories@github.com
https://github.com/envoyproxy/envoy/releases/tag/v1.39.1 security-advisories@github.com
https://github.com/envoyproxy/envoy/security/advisories/GHSA-23xh-2qxr-3xv8 security-advisories@github.com

Data sources

NVD CVE API 2.0 — fetched 2026-10-27 06:54 UTC · record ↗

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CVE-2026-73552

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