# CVE-2026-72588: Checkmate user enumeration via password recovery endpoint

Source: https://junglewise.ai/threats/cve-2026-72588-checkmate-user-enumeration-via-password-recovery-endpoint  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-10. Updated: 2026-09-25  
License: CC BY 4.0 with a link back

CVE-2026-72588 · Severity: medium · CVSS 5.3 · Published 2026-08-10

Checkmate is an open-source server monitoring and uptime tracking tool. An unauthenticated attacker can enumerate valid user email addresses by sending password recovery requests and observing different HTTP response codes. This allows adversaries to build a list of registered accounts without authentication, facilitating targeted attacks like brute-force or phishing campaigns.

Technologies: [Bluewave-Labs Checkmate](https://junglewise.ai/threats/technologies/checkmate). Vendors: [Bluewave-Labs](https://junglewise.ai/threats/vendors/bluewave-labs).

## Quick answers

**Is CVE-2026-72588 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-72588 being exploited in the wild.

**How severe is CVE-2026-72588?** Medium severity, with a CVSS score of 5.3, published 10 August 2026.

**Which products and versions are affected?** Bluewave-Labs Checkmate through 2.1.0.

**Is there a fix for CVE-2026-72588?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-72588 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-72588?** Check whether you run Bluewave-Labs Checkmate 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 user enumeration flaw in the POST /api/v1/auth/recovery/request endpoint. The endpoint returns HTTP 200 for registered email addresses and a different status code for unregistered addresses, enabling attackers to distinguish between valid and invalid accounts. No authentication is required to exploit this issue; attackers can submit arbitrary email addresses and observe response codes. This allows systematic enumeration of the application's user base, which can be used to facilitate further attacks such as credential stuffing, phishing, or account-targeted exploitation. Patches are available in newer versions beyond 2.1.0.

## Affected products

- bluewave-labs Checkmate through 2.1.0

## Timeline

- 2026-08-10: disclosed

## References

- [https://github.com/bluewave-labs/Checkmate](https://github.com/bluewave-labs/Checkmate)

## Related threats

- [Checkmate missing role guard middleware on maintenance and check routes](https://junglewise.ai/threats/cve-2026-85390-checkmate-missing-role-guard-middleware-on-maintenance-and-check)
- [Bluewave Labs Checkmate privilege escalation in invite endpoint](https://junglewise.ai/threats/cve-2026-36102-bluewave-labs-checkmate-privilege-escalation-in-invite-endpoint)
- [Checkmate credential exposure in public status pages](https://junglewise.ai/threats/cve-2026-71862-checkmate-credential-exposure-in-public-status-pages)
- [Bluewave Labs Checkmate denial of service via unvalidated file upload](https://junglewise.ai/threats/cve-2026-55241-bluewave-labs-checkmate-denial-of-service-via-unvalidated-file)