GHSA-725m-w832-q973: composer/composer (CVE-2015-8371)

Package	Ecosystem	Affected	Fixed in
composer/composer	Packagist	<1.0.0	1.0.0

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Composer, affected versions before 1.0.0, can have its dist package cache poisoned by other projects built on the same host. An attacker who controls one such project can place code into the cache, and that code then enters a server-side build process of another project. The source gives few details on the exact attacker position required. Upgrade to composer/composer 1.0.0 or later, which is listed as the fixed version.

Written 4 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

Score	Rating	CVSS	Vector	Source
8.8	High	3.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H	GitHub Advisory Database

CISA KEV Not listed.
EPSS 0.0072, the 54th percentile, on 11 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

31 Oct 2026, 14:32 UTC First seen by agentprime
31 Oct 2026, 14:32 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.