# CVE-2026-58122: nesquena Hermes WebUI authentication bypass in onboarding endpoints

Source: https://junglewise.ai/threats/cve-2026-58122-nesquena-hermes-webui-authentication-bypass-in-onboarding  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-07-09. Updated: 2026-07-09  
License: CC BY 4.0 with a link back

CVE-2026-58122 · Severity: critical · CVSS 9.1 · Published 2026-07-09

Hermes WebUI, a management interface for Large Language Model (LLM) services, contains a security flaw in its initial setup process. An attacker can trick the system into thinking they are accessing it from the local server by spoofing network headers. This allows them to bypass security checks to steal sensitive API keys, modify AI provider settings, or gain permanent access to the system.

## Quick answers

**Is CVE-2026-58122 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-58122 being exploited in the wild.

**How severe is CVE-2026-58122?** Critical severity, with a CVSS score of 9.1, published 9 July 2026.

**Which products and versions are affected?** nesquena Hermes WebUI < 0.51.307.

**Is there a fix for CVE-2026-58122?** A patch was published on 2026-06-06: Fix committed in version 0.51.307 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-58122 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-58122?** Check whether anything you run is named in the advisory. 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

An authentication bypass vulnerability exists in the onboarding gate of Hermes WebUI due to improper validation of the X-Forwarded-For and X-Real-IP HTTP headers. By supplying a loopback address (e.g., 127.0.0.1) in these headers, a remote unauthenticated attacker can bypass IP-based restrictions intended to limit onboarding access to local users. Successful exploitation allows the attacker to perform Server-Side Request Forgery (SSRF) against internal metadata endpoints, overwrite LLM provider configurations and API keys, or initiate OAuth device-code flows to obtain persistent access tokens. The issue is fixed in version 0.51.307 by ignoring forwarded headers for locality checks unless explicitly configured via the HERMES_WEBUI_TRUST_FORWARDED_FOR environment variable.

## Affected products

- nesquena Hermes WebUI < 0.51.307

## Timeline

- 2026-06-06: patched: Fix committed in version 0.51.307
- 2026-07-09: disclosed: CVE published and NVD record created

## References

- [https://github.com/nesquena/hermes-webui/commit/70596e6993be0d4cee083c1c1a86f5e7ad5d57b7](https://github.com/nesquena/hermes-webui/commit/70596e6993be0d4cee083c1c1a86f5e7ad5d57b7)
- [https://github.com/nesquena/hermes-webui/pull/3758](https://github.com/nesquena/hermes-webui/pull/3758)
- [https://github.com/nesquena/hermes-webui/releases/tag/v0.51.307](https://github.com/nesquena/hermes-webui/releases/tag/v0.51.307)
- [https://www.vulncheck.com/advisories/hermes-webui-authentication-bypass-via-x-forwarded-for-header-spoofing](https://www.vulncheck.com/advisories/hermes-webui-authentication-bypass-via-x-forwarded-for-header-spoofing)