Cross-site Scripting (XSS) Affecting php-league-commonmark package, versions <2.9.0-1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIANUNSTABLE-PHPLEAGUECOMMONMARK-18614886
- published11 Aug 2026
- disclosed6 Aug 2026
Introduced: 6 Aug 2026
CVE-2026-71478 (opens in a new tab)How to fix?
Upgrade Debian:unstable php-league-commonmark to version 2.9.0-1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream php-league-commonmark package and not the php-league-commonmark package as distributed by Debian.
See How to fix? for Debian:unstable relevant fixed versions and status.
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.