WP-GeSHi-Highlight <= 1.4.3 Authenticated (Author+) ReDoS

Am I affected?

• Check your version: in wp-admin go to Plugins → Installed Plugins and read the version under WP-GeSHi-Highlight — rock-solid syntax highlighting for 259 languages.
• No admin access? Run a passive check of your site. It reads public files only.

What to do

1. No known patch available. Please review the vulnerability's details in depth and employ mitigations based on your organization's risk tolerance. It may be best to uninstall the affected software and find a replacement.
2. Rotate administrator passwords and application secrets if the site ran a vulnerable version while publicly reachable.
3. Watch WP-GeSHi-Highlight — rock-solid syntax highlighting for 259 languages to get an email when the next vulnerability is published.

Advisory

Source description from Wordfence Intelligence, credited to Pierre Rudloff.

The WP-GeSHi-Highlight — rock-solid syntax highlighting for 259 languages plugin for WordPress is vulnerable to Regex denial of service in all versions up to, and including, 1.4.3. This is due to the plugin not properly restricting regexes supplied to the wp_geshi_filter_replace_code() function. This makes it possible for authenticated attackers, with Author-level access and above, to cause a denial of service based on a bad regex.

Exploits & references

Proof-of-concept & detection

No public proof-of-concept or detection template is known for this vulnerability.

Advisories & patches

• Advisorywordfence.com

Timeline

1. Mar 20, 2025

   CVE published

   Severity medium, CVSS 4.3

2. Nov 13, 2026

   Record last updated