GHSA-g6xq-892h-64w3
MEDIUMComposer: URL-embedded HTTP-Basic username leaks to verbose logs (GitHub PAT exposure)
Blast Radius
composer/composer🐘composer/composerReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Summary
When Composer is run with -vvv (debug verbosity), it could print a credential that was embedded directly in a repository or package URL, but not as a password, to its debug output. Composer already masked the password portion of such URLs, but the username portion was shown in clear text. Because GitHub and several other services support placing an access token in the username position of a URL (for example https://[token]@github.com/owner/repo), a token used that way could end up written to the verbose log in full.
This is an information disclosure issue. The credential is only ever exposed to whoever can already read Composer's debug output.
Am I affected?
You are potentially affected only if all of the following apply:
- A credential is embedded inside a URL that Composer handles, e.g. in a
repositoriesentry in composer.json, in a package dist/source URL - rather than being supplied through auth.json or the COMPOSER_AUTH environment variable. - The secret sits in the username slot of that URL (e.g.
https://TOKEN@host/…). A normalusername:password@hostpair where the username is an ordinary account name did not expose the password, that was already masked. - Composer is run with -vvv (debug verbosity), and that output is retained or shared somewhere others can read it: public CI build logs, output pasted into an issue or chat, archived terminal sessions, and so on.
If you keep credentials in auth.json or environment variables, or you never run Composer at debug verbosity, you were not exposed.
The most realistic exposure is the documented pattern of embedding a GitHub Personal Access Token in a URL's username position on a machine (often CI) that captures verbose output.
Patched versions
The username is now masked the same way the password already was, so an embedded token no longer appears in verbose output (a short, non-secret prefix may be shown to aid debugging, but never the full value).
Fixed in Composer 2.10.2 and the 2.2.29.
Workarounds
There is no configuration setting that prevents outputting credentials while keeping normal behavior.
If you cannot upgrade right away, you can reduce exposure by:
- Not running Composer with -vvv (debug verbosity) in environments where output is captured or shared.
- Moving credentials out of URLs and into auth.json or COMPOSER_AUTH.
- Scrubbing existing CI/build logs that may already contain a leaked token.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | composer/composer | ≥ 2.3.0&&< 2.10.2 | 2.10.2 |
| 🐘Packagist | composer/composer | ≥ 1.0.0&&< 2.2.29 | 2.2.29 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for composer/composer. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update composer/composer to 2.10.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-g6xq-892h-64w3 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether GHSA-g6xq-892h-64w3 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.
Tailored to GHSA-g6xq-892h-64w3. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-g6xq-892h-64w3 in your dependencies?
O3 detects GHSA-g6xq-892h-64w3 across Packagist dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.