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CVE-2025-46734

CVE-2025-46734 · league/commonmark Cross-site Scripting vulnerability in Attributes extension

This page contains facts from public vulnerability sources. Check the original advisory before updating.

league/commonmark is a PHP Markdown parser. A cross-site scripting (XSS) vulnerability in the Attributes extension of the league/commonmark library (versions 1.5.0 through 2.6.x) allows remote attackers to insert malicious JavaScript calls into HTML. The league/commonmark library provides configuration options such as `html_input: 'strip'` and `allow_unsafe_links: false` to mitigate cross-site scripting (XSS) attacks by stripping raw HTML and disallowing unsafe links. However, when the Attributes Extension is enabled, it introduces a way for users to inject arbitrary HTML attributes into elements via Markdown syntax using curly braces. Version 2.7.0 contains three changes to prevent this XSS attack vector: All attributes starting with `on` are considered unsafe and blocked by default; support for an explicit allowlist of allowed HTML attributes; and manually-added `href` and `src` attributes now respect the existing `allow_unsafe_links` configuration option. If upgrading is not feasible, please consider disabling the `AttributesExtension` for untrusted users and/or filtering the rendered HTML through a library like HTMLPurifier.

CVSS 6.4 · Medium · EPSS 0.4% · Fix available

Published
Updated

Stack: system · php

Affected products and versions

  • commonmark

    Versions
    • < 2.7.0: Affected

    No fix published

  • php-league-commonmark Debian:12

    Versions
    • 2.3.9-1
    Affected ranges
    • ECOSYSTEM: < 2.3.9-1+deb12u1

    Update to 2.3.9-1+deb12u1

  • php-league-commonmark Debian:13

    Affected ranges
    • ECOSYSTEM: < 2.7.0-1

    Update to 2.7.0-1

  • php-league-commonmark Debian:14

    Affected ranges
    • ECOSYSTEM: < 2.7.0-1

    Update to 2.7.0-1

  • league/commonmark Packagist

    Versions
    • 1.5.0
    • 1.5.1
    • 1.5.2
    • 1.5.3
    • 1.5.4
    • 1.5.5
    • 1.5.6
    • 1.5.7
    • 1.5.8
    • 1.6.0
    • 1.6.1
    • 1.6.2
    • 1.6.3
    • 1.6.4
    • 1.6.5
    • 1.6.6
    • 1.6.7
    • 2.0.0
    • 2.0.0-beta1
    • 2.0.0-beta2
    • 2.0.0-beta3
    • 2.0.0-rc1
    • 2.0.0-rc2
    • 2.0.1
    • 2.0.2
    • 2.0.3
    • 2.0.4
    • 2.1.0
    • 2.1.1
    • 2.1.2
    • 2.1.3
    • 2.2.0
    • 2.2.1
    • 2.2.2
    • 2.2.3
    • 2.2.4
    • 2.2.5
    • 2.3.0
    • 2.3.1
    • 2.3.2
    • 2.3.3
    • 2.3.4
    • 2.3.5
    • 2.3.6
    • 2.3.7
    • 2.3.8
    • 2.3.9
    • 2.4.0
    • 2.4.1
    • 2.4.2
    • 2.4.3
    • 2.4.4
    • 2.5.0
    • 2.5.1
    • 2.5.2
    • 2.5.3
    • 2.6.0
    • 2.6.1
    • 2.6.2
    Affected ranges
    • ECOSYSTEM: ≥ 1.5.0, < 2.7.0

    Update to 2.7.0

  • php-league-commonmark Ubuntu:Pro:20.04:LTS

    Versions
    • 1.1.2-1
    • 1.2.0-1
    • 1.3.0-1
    • 1.3.1-1
    • 1.3.1-1ubuntu2
    Affected ranges
    • ECOSYSTEM: < 1.3.1-1ubuntu2+esm1

    Update to 1.3.1-1ubuntu2+esm1

  • php-league-commonmark Ubuntu:Pro:22.04:LTS

    Versions
    • 1.5.7-2build1
    • 1.6.6-1build1
    • 1.6.7-1
    Affected ranges
    • ECOSYSTEM: < 1.6.7-1ubuntu0.1~esm1

    Update to 1.6.7-1ubuntu0.1~esm1

  • php-league-commonmark Ubuntu:Pro:24.04:LTS

    Versions
    • 2.3.9-1
    • 2.4.1-1
    • 2.4.2-1
    • 2.4.2-2
    Affected ranges
    • ECOSYSTEM: < 2.4.2-2ubuntu0.1~esm1

    Update to 2.4.2-2ubuntu0.1~esm1

Original sources

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