Server-Side Request Forgery (SSRF) in distribution - CVE-2026-33540
Published: April 8, 2026
Vulnerability identifier: #VU125341
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-33540
CWE-ID: CWE-918
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to disclose sensitive information.
The vulnerability exists due to server-side request forgery in pull-through cache proxy authentication when processing a WWW-Authenticate bearer realm from an upstream registry. A remote attacker can cause distribution to send configured upstream credentials via basic authentication to an attacker-controlled realm URL to disclose sensitive information.
This issue is exploitable if the configured upstream registry is attacker-controlled or if an attacker can intercept and modify the upstream connection.
Affected software
distribution
Fedora
docker-distribution
Fedora
docker-distribution
How to mitigate CVE-2026-33540
Install security update from vendor's website.
distribution - update to 3.1.0
docker-distribution - update to 3.1.1-1.fc45
docker-distribution - update to 3.1.1-1.fc45