CVE-2026-18937 Broken Link Checker < 2.4.12 - Unauthenticated RCE via Query Variable Injection
Unauthenticated attackers can execute arbitrary code on WordPress sites using plain permalinks and classic themes via query variable injection in the Broken Link Checker plugin.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-18937?
CVE-2026-18937 is a critical code injection vulnerability in Unknown Broken Link Checker, published on 19 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
The Broken Link Checker WordPress plugin before 2.4.12 does not limit which query variables it accepts from user input on sites using plain permalinks, allowing unauthenticated users to overwrite arbitrary PHP global variables, and to execute arbitrary code on the server when a classic (non-block) is active.
Weakness: CWE-94
Which versions are affected by CVE-2026-18937?
How do I fix CVE-2026-18937?
No fix has been published for CVE-2026-18937 yet. Limit exposure of the affected software until one is available.
Upgrade, and never evaluate templates, expressions or code built from user input. More about Code injection.
Is CVE-2026-18937 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-18937 exists.
Public exploit code: 1 Nuclei template and 1 proofs of concept on GitHub.
Sources
Also known as GHSA-c2xc-88v3-37g2.