# Prometheus basic authentication bypass in exporter-toolkit

Source: https://junglewise.ai/threats/prometheus-basic-authentication-bypass-in-exporter-toolkit-f8e091e2  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2022-12-05. Updated: 2026-05-11  
License: CC BY 4.0 with a link back

Severity: high · CVSS 7.2 · Published 2022-12-05

Prometheus, a popular monitoring and alerting toolkit, contains a vulnerability in its basic authentication mechanism. An attacker who has obtained a user's hashed password can bypass the authentication process to gain unauthorized access to the monitoring data. This could lead to the exposure of sensitive operational metrics or unauthorized configuration changes.

Technologies: [Prometheus](https://junglewise.ai/threats/technologies/prometheus). Vendors: [Prometheus](https://junglewise.ai/threats/vendors/prometheus).

## Quick answers

**Is This vulnerability exploited in the wild?** No. Junglewise Threat Intelligence has no report of This vulnerability being exploited in the wild.

**How severe is This vulnerability?** High severity, with a CVSS score of 7.2, published 5 December 2022.

**Which products and versions are affected?** Prometheus Exporter-Toolkit All versions prior to fixes in Prometheus 2.37.4/2.40.4; Prometheus >= 2.24.1, < 2.37.4; >= 2.38.0, < 2.40.4.

**Is there a fix for This vulnerability?** 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 This vulnerability attacked?** It is attacked over the network, in a software library.

**Am I affected?** Check whether you run Prometheus Exporter-Toolkit or Prometheus 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

A vulnerability exists in the Prometheus exporter-toolkit where the internal cache used for bcrypt hash computations can be poisoned. While Prometheus uses bcrypt to secure passwords in the web.yml file, an attacker who already possesses the hashed password (e.g., via disk access) can forge a request to poison this cache. This allows subsequent authentication attempts using the hash to succeed without knowing the original plaintext password. The cache is intended to mitigate side-channel attacks by normalizing response times for both valid and invalid users, but its implementation allows for this bypass. The issue is resolved in Prometheus versions 2.37.4 (LTS) and 2.40.4.

## Affected products

- Prometheus Prometheus >= 2.24.1, < 2.37.4; >= 2.38.0, < 2.40.4
- Prometheus exporter-toolkit All versions prior to fixes in Prometheus 2.37.4/2.40.4

## Timeline

- 2022-11-29: disclosed: Advisory published by Prometheus maintainers
- 2022-12-05: advisory: GitHub Advisory published

## References

- [https://api.github.com/users/chunklhit](https://api.github.com/users/chunklhit)
- [https://github.com/chunklhit](https://github.com/chunklhit)
- [https://api.github.com/users/chunklhit/gists%7B/gist_id%7D](https://api.github.com/users/chunklhit/gists%7B/gist_id%7D)
- [https://api.github.com/users/chunklhit/repos](https://api.github.com/users/chunklhit/repos)
- [https://avatars.githubusercontent.com/u/99457708?v=4](https://avatars.githubusercontent.com/u/99457708?v=4)
- [https://api.github.com/users/chunklhit/events%7B/privacy%7D](https://api.github.com/users/chunklhit/events%7B/privacy%7D)

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- [Prometheus remote_write credential leak via cross-host redirects](https://junglewise.ai/threats/cve-2026-119566-prometheus-through-3-15-1-contains-a-credential-leak)
- [Prometheus stored XSS in legacy web UI heatmap chart](https://junglewise.ai/threats/cve-2026-44903-prometheus-stored-xss-in-legacy-web-ui-heatmap-chart)
- [Prometheus denial of service via memory exhaustion in remote read endpoint](https://junglewise.ai/threats/cve-2026-42154-prometheus-denial-of-service-via-memory-exhaustion-in-remote-read)
- [Prometheus information disclosure in Azure AD OAuth configuration](https://junglewise.ai/threats/cve-2026-42151-prometheus-information-disclosure-in-azure-ad-oauth-configuration)