A AegiFlow
MEDIUMCVSS 6.1EPSS 0.2%

CVE-2026-71478

CVE-2026-71478 updated by NVD

Published
2026-08-06
Modified
2026-09-12
EPSS percentile
10%
Sources
github-advisory, nvd

Summary

league/commonmark is a PHP library for parsing and rendering CommonMark Markdown. From 1.5.0 until 2.9.0, the AttributesExtension's href and src unsafe-link filter can be bypassed by embedding control bytes, such as a tab, carriage return, line feed, or leading C0 control character, in a javascript: URL that browsers discard before parsing the scheme, causing the browser to still execute the script even when the unsafe-link filter is enabled. This issue is fixed in 2.9.0.

Affected packages

EcosystemPackageAffected versionsFixed versions
Packagistleague/commonmark2.9.0

Remediation: Upgrade to 2.9.0 or later.

References

Includes data from the GitHub Advisory Database, licensed under CC-BY 4.0.

Includes data from the National Vulnerability Database (NIST). NVD data is in the public domain; this page is not endorsed by NIST.

CVE® is a registered trademark of The MITRE Corporation. CVE content reproduced under the CVE Terms of Use; copyright designation © MITRE.

EPSS scores provided by the FIRST.org Exploit Prediction Scoring System.