# CVE-2025-26042: Uptime Kuma ReDoS in pushdeer and whapi notification providers

Source: https://junglewise.ai/threats/cve-2025-26042-uptime-kuma-redos-in-pushdeer-and-whapi-notification-providers  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-03-31. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2025-26042 · Severity: medium · CVSS 4 · Published 2025-03-31

Uptime Kuma is a popular open-source status page and monitoring application. Administrators can configure notifications through pushdeer and whapi services. A ReDoS (Regular Expression Denial of Service) vulnerability in the URL validation logic allows an attacker to craft a malicious URL that causes the application to hang or become unresponsive, disrupting monitoring and alerting capabilities and degrading service availability.

Technologies: [uptime-kuma (npm)](https://junglewise.ai/threats/technologies/uptime-kuma). Vendors: [npm](https://junglewise.ai/threats/vendors/npm).

## Quick answers

**Is CVE-2025-26042 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-26042 being exploited in the wild.

**How severe is CVE-2025-26042?** Medium severity, with a CVSS score of 4, published 31 March 2025.

**Which products and versions are affected?** uptime-kuma (npm) SEMVER:introduced=1.15.0,last_affected=1.23.16.

**Is there a fix for CVE-2025-26042?** A patch was published on 2025-03-29: Patch available in version 2.0.0-beta.2 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2025-26042 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2025-26042?** Check whether you run uptime-kuma (npm) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a Regular Expression Denial of Service (ReDoS) caused by catastrophic backtracking in the regex pattern `/\/*$/` used to strip trailing slashes from URLs in the pushdeer.js and whapi.js notification providers. When an attacker provides a URL containing a large number of repeated forward slashes followed by a non-slash character (e.g., "https://e" + "/" repeated 100,000 times + "@"), the regex engine enters excessive backtracking, consuming significant CPU resources and causing the web service to freeze for over 2 seconds. Attack requires administrator privileges to configure notifications through the web interface. The vulnerability affects versions 1.15.0 through 1.23.16, and 2.0.0-beta.0 and 2.0.0-beta.1, with a patch available in version 2.0.0-beta.2.

## Affected products

- Uptime Kuma Uptime Kuma >=1.15.0, <=1.23.16, 2.0.0-beta.0, 2.0.0-beta.1

## Identifiers

- CVE-2025-26042
- GHSA-hx7h-9vf7-5xhg

## Timeline

- 2025-03-31: disclosed
- 2025-03-29: patched: Patch available in version 2.0.0-beta.2

## References

- [https://github.com/louislam/uptime-kuma/security/advisories/GHSA-hx7h-9vf7-5xhg](https://github.com/louislam/uptime-kuma/security/advisories/GHSA-hx7h-9vf7-5xhg)

## Related threats

- [Uptime Kuma missing authorization check on ping badge endpoint](https://junglewise.ai/threats/cve-2026-32230-uptime-kuma-missing-authorization-check-on-ping-badge-endpoint)
- [Uptime Kuma Server-side Template Injection in notification templates](https://junglewise.ai/threats/uptime-kuma-server-side-template-injection-in-notification-templates-8547405a)
- [Uptime Kuma ReDoS in notification provider configuration](https://junglewise.ai/threats/uptime-kuma-redos-in-notification-provider-configuration-e7e79209)
- [Uptime Kuma authenticated remote code execution via plugin installation](https://junglewise.ai/threats/cve-2023-36821-uptime-kuma-authenticated-remote-code-execution-via-plugin)
- [Uptime Kuma path traversal in plugin installation](https://junglewise.ai/threats/cve-2023-36822-uptime-kuma-path-traversal-in-plugin-installation)