# Link Whisper Free <= 0.9.7 - Authenticated (Contributor+) PHP Object Injection via Link Whisper Post Meta

- **ID:** WPSEC-2026-0867
- **Plugin:** Link Whisper Free (`link-whisper`), https://wordpress.org/plugins/link-whisper/
- **Affected versions:** all versions before 0.9.8
- **Fixed in:** 0.9.8 (Update to 0.9.8 or later.)
- **Severity:** High 7.5 (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H)
- **Weakness:** CWE-502
- **Usage among sites WPSec scans:** plugin Medium, affected versions Medium (as of 2026-10-13)
- **Attack surface analysis:** https://attacksurface.wpsec.com/plugin/link-whisper
- **Fix released:** 2026-10-13
- **Published:** 2026-10-14
- **URL:** https://wpsec.com/vuln/WPSEC-2026-0867/

## Description

The Link Whisper Free plugin for WordPress is vulnerable to PHP Object Injection in all versions up to, and including, 0.9.7 via deserialization of the plugin's stored link data meta, which was passed to maybe_unserialize() without restricting the allowed classes and was not protected from generic custom field editing. This makes it possible for authenticated attackers with Contributor-level access and above, who can edit post meta on their own posts, to inject a PHP object. No known POP chain is present in the plugin itself; if a POP chain is present via another installed plugin or theme, it could allow the attacker to delete arbitrary files, retrieve sensitive data, or execute code.

## References

- https://wpsec.com/vuln/WPSEC-2026-0867/
- https://plugins.svn.wordpress.org/link-whisper/tags/0.9.8/
- https://wordpress.org/plugins/link-whisper/

Source: WPSec, https://wpsec.com/vuln/WPSEC-2026-0867/

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.