Critical Red Hat Quay Flaw Lets Attackers Take Over Registry Token Signing

Red Hat has disclosed a critical vulnerability in Red Hat Quay, its enterprise container registry for storing, managing, and distributing container images. The flaw is tracked as CVE-2026-123710 and has a CVSS 3.1 score of 9.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H). It lets an attacker take over registry token signing and gain full read and write access to every repository in the registry.

How the attack works
The flaw is in Quay’s service key server, the component that manages signing keys. Deployments are affected when this service can be reached by untrusted clients. The attack chain is:

1. If anonymous access is enabled, an unauthenticated client gets an anonymous registry token with an audience it controls.
2. The attacker presents that token to the service key rotation endpoint.
3. The attacker installs their own approved signing key, with no expiry date.
4. Registry tokens signed with the attacker’s key are accepted for any repository, giving read and write access to private images and the ability to replace repository tags.

Impact

• Data exposure: Attackers can pull private images, along with any credentials, API keys, or other secrets built into them.
• Supply chain compromise: Attackers can overwrite images and tags, so systems that later pull them, such as CI/CD pipelines and Kubernetes clusters, could deploy malicious code.
• Persistence: The malicious signing key has no expiry and survives registry restarts unless it is removed manually. Changing passwords or regenerating robot tokens does not invalidate it.
• Disruption: According to Red Hat’s Bugzilla report, rotation also deletes the legitimate instance key as a side effect, and the attacker’s key can delete replacement instance keys. This could stop legitimate users from pushing or pulling images.

Disabling anonymous access is not enough
Red Hat warns that turning off anonymous access does not protect against the flaw, because any valid Quay account can still exploit it. In practice, any user with an account, or any attacker with stolen credentials, can escalate to full control over the registry.

Patch status
Neither Red Hat’s advisory nor the Bugzilla report names a fixed version yet. However, fixes for this vulnerability and a second Quay flaw, CVE-2026-110697, were merged into the project’s GitHub repository on November 11, 2026. Red Hat warns that attackers could reinstall malicious keys until a fix is deployed.

Discovery
The vulnerability was discovered by Dave O’Connor of Red Hat.

Recommendations

• Restrict access to the service key management endpoints so untrusted clients and networks cannot reach them.
• Review logs for suspicious service key creation, rotation, or deletion, especially keys with no expiry date.
• Remove unauthorized signing keys and restore the legitimate instance key if it has been deleted.
• Keep checking for malicious keys until a patched release is deployed, since attackers can reinstall them.
• Verify image integrity by checking repositories for unexpected tag changes or image overwrites, and confirm image digests and signatures before deployment.
• Rotate secrets stored in container images in exposed registries, as a precaution.
• Apply the official fix as soon as Red Hat releases a patched Quay version, and watch the advisory for updates.