Critical security advisoryCriticalFlagged by our vulnerability database: PHP2Shell is on CISA’s exploited list. Most WordPress hosting runs PHP. See if your site is affectedFlagged by our vulnerability database: PHP2Shell is being exploited. DetailsExploited: PHP2Shell. Check your site
HuttenlocherTechnologies
MediumCVSS 6.4Other software

CVE-2025-46734

league/commonmark is a PHP Markdown parser.

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.

Description from the National Vulnerability Database, published by GitHub

What to do: Apply the vendor’s update. The NVD record links to the advisory.

What it means for a small business

If your business uses commonmark, install the vendor's update. If you're not sure whether you use it, ask whoever manages your computers.

How likely is an attack? The Exploit Prediction Scoring System, run by FIRST (the global association of security response teams), puts the odds of this one being exploited in the next 30 days at 0.38%, higher than 31% of CVEs. That’s low, but low isn’t zero, and the odds jump the day someone publishes an exploit. Scored October 28, 2026, updated daily.

Check your own setup

  • Website check: reads what your site runs from the outside (WordPress version, plugins it can see, old server software) and matches it against this database.
  • Server check: what your web server says about itself, and whether that version has known flaws.

Part of the Huttenlocher Technologies vulnerability database, refreshed twice a day from CISA and the NVD. The title, category and plain-language guidance are ours; check the linked record before acting on a detail. This is general guidance, not a review of your systems.

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