Upstream information

CVE-2026-33540 at MITRE

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.

Upstream Security Advisories:

SUSE information

Overall state of this security issue: New

This issue is currently rated as having important severity.

CVSS v3 Scores
CVSS detail CNA (GitHub)
Base Score 7.5
Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack Vector Network
Attack Complexity Low
Privileges Required None
User Interaction None
Scope Unchanged
Confidentiality Impact High
Integrity Impact None
Availability Impact None
CVSSv3 Version 3.1
No SUSE Bugzilla entries cross referenced.

SUSE Security Advisories:

SUSE Timeline for this CVE

CVE page created: Mon Apr 6 17:27:43 2026
CVE page last modified: Mon Apr 6 20:43:16 2026