Medium [CVE-2026-74240] JWT claim validation bypasses in Quay federated robot and SSO authentication
This medium-severity Red Hat Linux advisory covers CVE-2026-74240 affecting Red Hat OpenShift Update Service, Red Hat Quay 3.
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Summary
A flaw was found in Red Hat Quay's JWT (JSON Web Token) validation for federated robot accounts and single sign-on (SSO) authentication. Multiple issues related to audience verification and the enforcement of `azp` and `sub` claims were identified.
These flaws could allow an attacker with a validly-signed token from the same identity provider to bypass configured security restrictions. This bypass could lead to unauthorized access by circumventing intended audience, subject, or authorized-client limitations.
This is due to default configurations for federated robot authentication not enforcing audience verification, and insufficient checks for 'azp' and 'sub' claims in certain scenarios. Exploitation requires a pre-existing valid token from the same IdP, limiting the attack surface.
Red Hat severity: Moderate — CVSS 5.4 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N). Weakness: CWE-287.
Affected Red Hat products: Red Hat OpenShift Update Service; Red Hat Quay 3. Red Hat does not currently list a fixing RHSA for this CVE.
Affected versions
No affected-version range was extracted from the source record. The vendor advisory is authoritative — check it before change work.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Fixed versions
No fixed release is recorded yet. That does not prove no patch exists — confirm against the vendor advisory.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
Mitigation checklist
- To mitigate this issue, Red Hat Quay administrators should ensure that federated robot authentication is configured with specific audiences to enable 'verify_aud' enforcement. Additionally, review and update existing federation configurations to explicitly include and enforce 'azp' and 'sub' claims, preventing bypasses when these claims are absent. Refer to Red Hat Quay documentation for detailed configuration steps. A restart of affected Quay services may be required after configuration changes.
Official advisory · high-confidence parse· fetched 2 hours ago·verify at source
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