Insufficiently protected credentials in composer - #VU165349
Published: November 11, 2026
Vulnerability identifier: #VU165349
CSH Severity: Medium
CVSS v4: 6.7 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-522
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to obtain a repository's inline HTTP header credential.
The vulnerability exists due to insufficiently protected credentials in Composer's repository header handling when reattaching secret-bearing headers to downloads from untrusted mirrors. A remote attacker can craft composer.lock or vendor/composer/installed.json to specify a preferred attacker-controlled download mirror and induce a victim to run composer install to receive the repository credential at that mirror.
Affected software
composer
Remediation
Install security update from vendor's website.
composer - addressed in versions 2.2.32, 2.11.2