CVE-2026-18937: unknown broken link checker Code Injection

Vulnerability summary

CVE-2026-18937 is a critical (CVSS 9.8) Code Injection vulnerability in unknown broken link checker. EPSS estimates a 0.54% chance of exploitation in the next 30 days, higher than 44.4% of scored vulnerabilities. 1 public exploit is recorded. Fixed in 2.4.12.

Timeline

1. 19-08-2026
   PublishedVulnerability first disclosed.
2. 19-08-2026
   Last modifiedVulnerability information updated.

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.

• CWE-94Improper Control of Generation of Code ('Code Injection')The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.