Buffer overflow in Composer
CVE-2026-59948
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.
Vulnerability class: Path Traversal (Directory Traversal)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.0 (High). Vector: CVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.002 (5.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 5th percentile — 5.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
- Composer — versions >= 1.0, < 2.2.29, >= 2.3.0, < 2.10.2
Weakness classification (CWE)
References
- github.com/composer/composer/security/advisories/GHSA-499r-g7pc-vmp9
- github.com/composer/composer/commit/502c6c4f699802d9cf464728b3e8a95674f919a0
- github.com/composer/composer/commit/c50b1efd13ebd73f6dca19b31424c5a02bf93cc1
- github.com/composer/composer/releases/tag/2.10.2
- github.com/composer/composer/releases/tag/2.2.29
Frequently asked questions
- What is CVE-2026-59948?
- CVE-2026-59948 is a high-severity vulnerability in Composer, classified under Path Traversal. CVSS score: 7.0/10. Published 2026-07-08.
- How severe is CVE-2026-59948?
- High severity. CVSS v3 base score is 7.0 out of 10.