CVE-2026-85747 distribution CVE debrief

Who should care

Container registry administrators, supply chain security teams, and developers using Distribution should assess exposure and prioritize remediation. This vulnerability affects any application relying on digest pinning for supply-chain integrity, including image policy controllers, mirrors, and pull-through caches. The bundled pull-through proxy is directly exploitable, and verification priority is high for affected Distribution versions.

Why it matters

CVE-2026-85747 allows a malicious registry or MITM to serve arbitrary manifest bytes, undermining supply chain integrity controls that rely on digest pinning.

• Potential bypass of supply chain integrity controls
• Possible exploitation by malicious registries or MITM attackers
• Impact on container registry and supply chain security
• Verification priority for affected Distribution versions

Technical summary

The Distribution client fails to verify the returned content against the requested digest, potentially allowing a malicious registry or MITM to serve arbitrary manifest bytes. This vulnerability affects container registry administrators, supply chain security teams, and developers using Distribution, and it undermines supply chain integrity controls that rely on digest pinning. The root cause of this vulnerability is in the `registry/client/repository.go` file, where the response body is read and passed directly to `distribution.UnmarshalManifest` without computing the digest from the body and comparing it against the caller-supplied digest.

Defensive priority

High priority for container registry and supply chain integrity defenders

Recommended defensive actions

• Review and update container registry configurations to ensure digest verification is enabled
• Verify and apply patches or updates to affected Distribution versions
• Implement additional supply chain integrity controls, such as image policy controllers
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up
• Review the supplied official advisory or CVE record to validate affected scope, severity, and vendor guidance
• Plan vendor-supported updates or mitigations through normal change control where exposure is confirmed
• Check relevant monitoring, detection, and logs for exposed assets that need extra review

Evidence notes

Evidence from the source corpus indicates that the Distribution client does not verify the returned content against the requested digest, potentially allowing a malicious registry or MITM to serve arbitrary manifest bytes.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.