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

> Attackers can view GitHub Personal Access Tokens in debug logs when Composer runs with high verbosity, exposing sensitive credentials.

- **Severity:** Medium 4.7 (`CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Jul 2026
- **Updated:** 9 Jul 2026
- **Also known as:** BIT-composer-2026-59947, CLEANSTART-2026-KK97612, DEBIAN-CVE-2026-59947, GHSA-g6xq-892h-64w3, MINI-h4f9-wh6v-6xjx, MINI-q7fc-848c-jx32, UBUNTU-CVE-2026-59947

## What is CVE-2026-59947?

CVE-2026-59947 is a medium-severity vulnerability in composer, published on 8 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official 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.

Weakness: CWE-532 (Insertion of Sensitive Information into Log File)

## Which versions are affected by CVE-2026-59947?

5 open source packages ship an affected version, including composer/composer and composer.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `composer/composer` | Packagist | From 1.0.0 | 2.2.29 |
| `composer/composer` | Packagist | From 1.0.0 | 2.2.29 |
| `composer/composer` | Packagist | From 2.3.0 | 2.10.2 |
| `composer/composer` | Packagist | From 2.3.0 | 2.10.2 |
| `composer` | Bitnami | From 1.0.0 | 2.2.29, 2.10.2 |

## How do I fix CVE-2026-59947?

Upgrade composer/composer to a fixed version for your release line: 2.2.29 or 2.10.2.

## Is CVE-2026-59947 being exploited?

There is no known exploitation of CVE-2026-59947 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-59947 and fix it if it is affected.

What it is: CVE-2026-59947 is a medium-severity vulnerability in composer, published on 8 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-59947 in the wild and no public exploit code.

Affected packages and fixed versions:
- composer/composer (Packagist): affected from 1.0.0; fixed in 2.2.29
- composer/composer (Packagist): affected from 1.0.0; fixed in 2.2.29
- composer/composer (Packagist): affected from 2.3.0; fixed in 2.10.2
- composer/composer (Packagist): affected from 2.3.0; fixed in 2.10.2
- composer (Bitnami): affected from 1.0.0; fixed in 2.2.29, 2.10.2

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-59947/ (Markdown: https://insights.sbomify.com/CVE-2026-59947/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-59947
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-59947
- OSV: https://osv.dev/vulnerability/CVE-2026-59947

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-59947/
Summaries are generated and may contain mistakes; the official description above is the record.