Information disclosure in Composer

CVE-2026-59947

Composer is a dependency Manager for the PHP language. Prior to 2.2.29 and 2.10.2, when Composer is run with -vvv debug verbosity, it could print a credential embedded in the username slot of a repository or package URL, such as a GitHub Personal Access Token in https://TOKEN@host/, to debug output because AuthHelper, Url::sanitize, and ProcessExecutor did not sanitize username-only URL credentials. This issue is fixed in versions 2.2.29 and 2.10.2.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.7 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.001 (3.2th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 3rd percentile — 3.2% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-59947: held from 0.001 to 0.001.

EPSS over last 30 days · oldest: 0.001 · newest: 0.001 · change: 0.000

Affected products

  • Composer — versions >= 1.0, < 2.2.29, >= 2.3.0, < 2.10.2

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-59947?
CVE-2026-59947 is a medium-severity vulnerability in Composer, classified under Insertion of Sensitive Information into Log File. CVSS score: 4.7/10. Published 2026-07-08.
How severe is CVE-2026-59947?
Medium severity. CVSS v3 base score is 4.7 out of 10.