Home Assistant MCP Server: YAML config backups written under www/ are served unauthenticated at /local/

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.5 · CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS

No dated EPSS signal available.

As published by the source; long descriptions are shortened.

Summary When ENABLEYAMLCONFIGEDITING=true, every haconfigsetyaml call backs up the pre-edit file to <config/www/yamlbackups/, which Home Assistant serves at /local/ with no authentication. Anyone who can reach the HA web interface can download the most recent pre-edit configuration.yaml (or other YAML file) — typically containing plaintext MQTT passwords, REST credentials, webhook IDs, geofence coordinates, and shellcommand definitions — with zero credentials. Details The backup feature is good — dobackup defaults to True and protects users from a bad edit. The issue is the location: - customcomponents/hamcptools/init.py:596 — backupdir = configdir / "www" / "yamlbackups" - customcomponents/hamcptools/init.py:602 — backupfile = backupdir / f"{safename}.{timestamp}.bak" - customcomponents/hamcptools/init.py:606-607,692-693 — backup path returned to caller and logged at INFO <config/www/ is /local/ and HA serves it unauthenticated by design (intended for static dashboard assets). An…

Published by the source

14 May 2026, 20:17 UTC

Last modified by the source

14 May 2026, 20:37 UTC

Source last checked

26 Oct 2026, 13:41 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-g39v-cvjh-8fpf

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-g39v-cvjh-8fpf

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# Patch Next advisory brief: GHSA-g39v-cvjh-8fpf

Advisory: Home Assistant MCP Server: YAML config backups written under www/ are served unauthenticated at /local/
IDs: GHSA-g39v-cvjh-8fpf
Record: https://patchnext.com/advisories/ghsa-g39v-cvjh-8fpf (revision 2, source checked 26 Oct 2026, 13:41 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: ha-mcp 7.5.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI ha-mcp: affected < 7.5.0; fixed in 7.5.0

## Suggested inspection (read-only)
- `python -m pip show ha-mcp`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on ha-mcp.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-g39v-cvjh-8fpf (OSV record GHSA-g39v-cvjh-8fpf lists affected ranges: PyPI ha-mcp >=0 <7.5.0 (fixed))
- Verified: https://github.com/advisories/GHSA-g39v-cvjh-8fpf (GitHub-reviewed advisory GHSA-g39v-cvjh-8fpf lists affected ranges: PyPI ha-mcp >=0 <7.5.0)

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