# Broken Link Checker <= 2.4.14.1 - Authenticated (Contributor+) PHP Object Injection via SiteOrigin panels_data Post Meta

- **ID:** WPSEC-2026-0918
- **Plugin:** Broken Link Checker (`broken-link-checker`), https://wordpress.org/plugins/broken-link-checker/
- **Affected versions:** all versions before 2.4.15
- **Fixed in:** 2.4.15 (Update to 2.4.15 or later.)
- **Severity:** High 7.1 (CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:H)
- **Weakness:** CWE-502
- **Usage among sites WPSec scans:** plugin Low, affected versions Low (as of 2026-10-14)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/broken-link-checker
- **Fix released:** 2026-10-12
- **Published:** 2026-10-14
- **URL:** https://wpsec.com/vuln/WPSEC-2026-0918/

## Description

The Broken Link Checker plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 2.4.14.1 via the SiteOrigin Page Builder panels_data post meta, due to the value returned by get_post_meta() being passed to maybe_unserialize() a second time when a Cloud broken link action (edit or unlink) processes the post. This makes it possible for authenticated attackers with contributor-level access and above to store a serialized PHP object in the panels_data custom field of their own post, which is instantiated when a site administrator runs a Cloud link action on a link in that post while SiteOrigin Page Builder is active. No known POP chain is present in the vulnerable software. If a POP chain is present via an additional plugin or theme installed on the target system, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code.

## References

- https://wpsec.com/vuln/WPSEC-2026-0918/
- https://plugins.svn.wordpress.org/broken-link-checker/tags/2.4.15/
- https://wordpress.org/plugins/broken-link-checker/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-0918/

License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Free to use, share and adapt, also commercially, if you credit WPSec and link to this advisory.