CVE-2026-33540

NameCVE-2026-33540
DescriptionDistribution is a toolkit to pack, ship, store, and deliver container content. Prior to 3.1.0, in pull-through cache mode, distribution discovers token auth endpoints by parsing WWW-Authenticate challenges returned by the configured upstream registry. The realm URL from a bearer challenge is used without validating that it matches the upstream registry host. As a result, an attacker-controlled upstream (or an attacker with MitM position to the upstream) can cause distribution to send the configured upstream credentials via basic auth to an attacker-controlled realm URL. This vulnerability is fixed in 3.1.0.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
docker-registry (PTS)bullseye (security), bullseye2.7.1+ds2-7+deb11u1vulnerable
bookworm2.8.2+ds1-1vulnerable
forky, sid, trixie2.8.3+ds1-2vulnerable

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
docker-registrysource(unstable)(unfixed)

Notes

https://github.com/distribution/distribution/security/advisories/GHSA-3p65-76g6-3w7r

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