Information disclosure in composer - #VU159578
Published: November 6, 2026
Vulnerability identifier: #VU159578
CSH Severity: Medium
CVSS v4: 5.6 [CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-200
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows an unauthenticated remote attacker to obtain repository credentials from a shared composer.lock file.
The vulnerability exists due to Composer copying options.http.header values into the lock file when downloading package archives under a Composer-type repository's URL, even when the repository is configured outside the project in global config.json. An unauthenticated remote attacker can read these credentials if a developer generates and shares the lock file with unauthorized readers.
Affected software
composer
Remediation
Install security update from vendor's website.
composer - addressed in versions 2.2.31, 2.11.0