# CVE-2026-18937: Broken Link Checker - RCE

> Live exploitation tracking for CVE-2026-18937 by the CrowdSec Live Exploit Tracker, built from real-world attack data crowdsourced from CrowdSec's global network.

Page: https://tracker.crowdsec.net/cves/CVE-2026-18937

## Key facts

- **Exploitation phase:** Limited Exploitation. The vulnerability is known but shows very limited attacker interest or exploitation activity.
- **CVSS score:** 9.0
- **Public exploit available:** Yes
- **Affected products:** WPmudev Broken Link Checker
- **Weaknesses:** CWE-94 (Improper Control of Generation of Code ('Code Injection'))
- **Tags:** wordpress, cms

## 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.

## CrowdSec analysis

[CVE-2026-18937](https://euvd.enisa.europa.eu/vulnerability/CVE-2026-18937) is a critical vulnerability in the Broken Link Checker WordPress plugin versions before 2.4.12. On sites using plain permalinks, unauthenticated attackers can manipulate PHP global variables through query parameters and, when a classic non-block theme is active, potentially execute arbitrary code on the server.

CrowdSec has been tracking this vulnerability and its exploits since 22nd of October 2026.

Data from the CrowdSec community indicates that exploitation of CVE-2026-18937 is highly selective and intelligence-driven. Threat actors use advanced reconnaissance and carefully choose their targets, often as part of sophisticated campaigns or advanced persistent threat operations.
Data from the CrowdSec community also indicates a gradual decrease in attacks targeting CVE-2026-18937. While still present in the wild, exploitation levels have dropped noticeably week-over-week. This may signal that the vulnerability is becoming less relevant or that defenses are improving fast enough for attackers to lose interest.

Attackers target the WordPress root endpoint (`/`) with crafted query parameters that overwrite widget and sidebar globals, invoking `system` to execute a command such as `id`.

## Timeline

- 2026-08-19: CVE Published. CVE-2026-18937 is published to NVD.
- 2026-10-22: Rule Released. CrowdSec releases a rule to detect CVE-2026-18937 exploitation attempts against the CrowdSec Network.
- 2026-10-28: CrowdSec First Seen. CrowdSec observes in-the-wild exploitation of CVE-2026-18937 for the first time.

## References

- https://wpscan.com/vulnerability/a23b76eb-107d-4e02-8eae-c3c5fa5b003d/
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2026/CVE-2026-18937.yaml

## Live exploitation data

The [Live Exploit Tracker page](https://tracker.crowdsec.net/cves/CVE-2026-18937) follows observed exploitation activity for CVE-2026-18937. [Request an API key](https://tracker.crowdsec.net/request-api-key) for full access to its exploitation timeline, attacking IP addresses and blocklists.