Composer up to 2.2.28/2.10.1 URL Sanitizer sanitize/ProcessExecutor Username log file

Summaryinfo

A vulnerability, which was classified as problematic, was found in Composer up to 2.2.28/2.10.1. Impacted is the function AuthHelper/Url::sanitize/ProcessExecutor of the component URL Sanitizer. Executing a manipulation of the argument Username can lead to log file. This vulnerability appears as CVE-2026-59947. The attack requires local access. There is no available exploit.

Detailsinfo

A vulnerability was found in Composer up to 2.2.28/2.10.1. It has been declared as problematic. This vulnerability affects the function AuthHelper/Url::sanitize/ProcessExecutor of the component URL Sanitizer. The manipulation of the argument username with an unknown input leads to a log file vulnerability. The CWE definition for the vulnerability is CWE-532. Information written to log files can be of a sensitive nature and give valuable guidance to an attacker or expose sensitive user information. As an impact it is known to affect integrity. CVE summarizes:

Composer is a dependency Manager for the PHP language. Prior to 2.2.29 and 2.10.2, when Composer is run with -vvv debug verbosity, it could print a credential embedded in the username slot of a repository or package URL, such as a GitHub Personal Access Token in https://TOKEN@host/, to debug output because AuthHelper, Url::sanitize, and ProcessExecutor did not sanitize username-only URL credentials. This issue is fixed in versions 2.2.29 and 2.10.2.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-59947 since 07/07/2026. The exploitation appears to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1592.

Upgrading to version 2.2.29 or 2.10.2 eliminates this vulnerability.

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

Name

• Composer

Version

• 2.2.0
• 2.2.1
• 2.2.2
• 2.2.3
• 2.2.4
• 2.2.5
• 2.2.6
• 2.2.7
• 2.2.8
• 2.2.9
• 2.2.10
• 2.2.11
• 2.2.12
• 2.2.13
• 2.2.14
• 2.2.15
• 2.2.16
• 2.2.17
• 2.2.18
• 2.2.19
• 2.2.20
• 2.2.21
• 2.2.22
• 2.2.23
• 2.2.24
• 2.2.25
• 2.2.26
• 2.2.27
• 2.2.28
• 2.10.0
• 2.10.1

Website

• Product: https://github.com/composer/composer/

CPE 2.3info

• 🔒
• 🔒
• 🔒

CPE 2.2info

• 🔒
• 🔒
• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

VulDB is the best source for vulnerability data and more expert information about this specific topic.

Discussion