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CVE PROGRAM SOURCE RECORD6.1 Medium

CVE-2026-71478

league/commonmark: AttributesExtension href/src unsafe-link filter bypass via embedded control bytes

Description

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 products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

thephpleague commonmark

  • >= 1.5.0, <= 2.8.3affected

References