CVE-2026-59948CWE-22CWE-787

Composer: Arbitrary file write outside vendor via malicious transitive package name

High · published July 8, 2026

CVSS v3.1
7.0
EPSS
0%
Percentile
2.9
In the wild
Unconfirmed
What it is

Composer is a dependency Manager for the PHP language. Prior to 2.2.29 and 2.10.2, a maliciously crafted package from an untrusted repository other than Packagist.org or Private Packagist can cause Composer to write attacker-controlled files outside the vendor directory and outside the project during install or update by using an invalid package name that is not correctly validated before dependency-resolution results are written or installed. This issue is fixed in versions 2.2.29 and 2.10.2.

The record
Technical detail
CVSS v3.1
7.0 · HIGH
Vector
CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00138 · 2.9th percentile
Weaknesses
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'); CWE-787 · Out-of-bounds Write
Published
2026-07-08T19:33Z
EPSS history
Timeline
  • 08 JUL 19:33Z
    Composer: Arbitrary file write outside vendor via malicious transitive package name
    cvelistv5