CVE-2026-33540
Last modified
CVE-2026-33540 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. Distribution 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. EPSS estimates a 0.27% chance of exploitation in the next 30 days.
Description
Distribution 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.
Metrics
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness Enumeration
Affected Software
| Vendor | Product | Versions |
|---|---|---|
| Distribution Project | Distribution | < 3.1.0 |
References
- https://github.com/distribution/distribution/security/advisories/GHSA-3p65-76g6-3w7rExploit, Mitigation, Vendor Advisory
- https://github.com/distribution/distribution/security/advisories/GHSA-3p65-76g6-3w7rExploit, Mitigation, Vendor Advisory
Timeline
- Published
- Last Modified
- Status
- Analyzed
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