A critical security vulnerability in Red Hat Quay, an enterprise container registry platform, could allow attackers to access private container images, modify repository contents and maintain persistent access to affected systems.
Tracked as CVE-2026-123710, the flaw carries a CVSS severity score of 9.8 out of 10, placing it in the critical category. According to Red Hat, the vulnerability affects deployments in which the service responsible for managing signing keys is accessible to untrusted clients.
The vulnerability exists in Quay's service key server, which manages the cryptographic keys used to sign registry access tokens. These tokens determine whether users and applications can download or upload container images.
According to Red Hat's security advisory, an unauthenticated attacker can exploit weaknesses in the key rotation mechanism to install an unauthorized signing key that the registry automatically trusts. When anonymous access is enabled, an attacker can obtain a registry token and use it to manipulate the key rotation process.
Once the malicious key has been installed, attackers can generate their own registry tokens with read and write permissions across repositories. This allows them to access private container images belonging to other users or organizations without following the platform's normal access restrictions.
According to Red Hat's Bugzilla report, "rotation also deletes the legitimate instance key as a side effect, and the attacker key can delete replacement instance keys."
Beyond stealing images, attackers could also replace or overwrite repository contents. Such modifications could affect software development and deployment processes, particularly when automated systems download compromised images from the registry. Sensitive credentials and other secrets stored within container images could also be exposed.
Another scaring aspect of the vulnerability is the persistence of unauthorized access. The malicious signing key can be configured without an expiration date and remains active even after the registry is restarted. Red Hat also warned that attackers could use the compromised key to delete legitimate signing keys, potentially disrupting normal image uploads and downloads.
Disabling anonymous access does not completely eliminate the risk, as users with valid Quay accounts can also exploit the vulnerability. Similarly, changing account passwords or regenerating robot account tokens will not invalidate an unauthorized signing key.
Red Hat recommends administrators immediately restrict access to the key-management service.
Red Hat cautioned that removing malicious keys alone may not provide lasting protection until a fixed version is installed, as attackers could potentially reinstall them.
The vulnerability was discovered by Red Hat researcher Dave O'Connor. Fixes for the issue were merged into the project's GitHub repository on November 11.
