Bug 2550755 (CVE-2026-85747)

Summary: CVE-2026-85747 github.com/distribution/distribution: distribution: Arbitrary container manifest substitution via missing digest verification
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
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OS: Linux   
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A flaw was found in Distribution. A remote attacker operating a malicious registry or intercepting network communications can substitute container image manifests with arbitrary content. This issue occurs because the client processes returned manifests for digest-pinned requests without verifying that the manifest body matches the expected cryptographic hash. Consequently, affected clients and caching proxies can accept, store, and redistribute untrusted container content.
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Description OSIDB Bzimport 2026-10-13 18:33:56 UTC 
Distribution is a toolkit to pack, ship, store, and deliver container content. Prior to 3.1.2, registry/client.(*manifests).Get() reads a manifest returned for a digest-pinned request and passes it to distribution.UnmarshalManifest without hashing the body against the requested digest, allowing a malicious or intercepted registry response to substitute attacker-chosen manifest content even when Docker-Content-Digest claims the requested value. The bundled pull-through proxy in registry/proxy/proxymanifeststore.go can cache and re-serve the substituted manifest. This issue is fixed in version 3.1.2.