claircore CVE-2026-16254

The attacker must hold a low-privileged account capable of pushing container images to a Red Hat Quay 3 registry or submitting images for scanning via Red Hat Advanced Cluster Security 4 (PR:L per CVSS vector). The vulnerability is triggered specifically when the Clair indexer processes the APK (Alpine Linux) package database within a container layer - images not containing APK package databases would not trigger it. The impact is limited to denial of service against the indexer process; exploitation does not grant code execution or data access. The crash occurs only if the Go panic from the out-of-bounds read is not caught by a recovery handler upstream in the call stack. Anonymous unauthenticated internet access is insufficient - some form of valid credentials to the container platform is required.

The CVSS 3.1 score of 4.3 (Medium) reflects a network-accessible, low-complexity attack requiring low privileges with no user interaction, but scoped to availability impact only (A:L). The attack vector is network (AV:N) and complexity is low (AC:L), meaning any user who can push container images to an affected Quay registry or submit images for ACS scanning can trigger this. EPSS data was not provided, and the CVE is not in the CISA KEV catalog, indicating no confirmed active exploitation. No public proof-of-concept code is identified at time of analysis. The real-world risk is bounded by the attacker needing low-privileged access to the container platform - this is not exploitable by anonymous internet actors against default-locked deployments. The primary business impact is disruption to container vulnerability scanning pipelines, not data exfiltration or code execution. The 'Information Disclosure' tag in the source intelligence conflicts with the C:N CVSS metric; until clarified by the Red Hat advisory, the confidentiality impact should be treated as unconfirmed. Overall this is a genuine but low-urgency availability issue for organizations running ACS 4 or Quay 3.

An attacker with a valid low-privileged account on an affected Red Hat Quay 3 instance pushes a crafted Alpine Linux container image whose APK package database layer contains malformed entries designed to trigger an out-of-bounds read in claircore's APK scanner. When the Clair indexer processes this image, the scanner panics, and if the panic propagates without recovery, the indexer process crashes - halting all vulnerability scanning for images in that registry until the process is restarted. No public proof-of-concept code is identified at time of analysis.