CVE-2026-71478
6.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
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 Software
| Vendor | Product | Version Range | Status |
|---|---|---|---|
| thephpleague | commonmark | >= 1.5.0, <= 2.8.3 | affected |
Weaknesses
- CWE-79: CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- CWE-86: CWE-86: Improper Neutralization of Invalid Characters in Identifiers in Web Pages
- CWE-692: CWE-692: Incomplete Denylist to Cross-Site Scripting
References
- https://github.com/thephpleague/commonmark/security/advisories/GHSA-29pj-957v-52mc
- https://github.com/thephpleague/commonmark/commit/493a5aa7d65754b73846006eaff9c2c4431a8e2c
- https://github.com/thephpleague/commonmark/releases/tag/2.9.0
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