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Home AssistantApplication

CVE-2023-41895

CRITICAL · 9.6 CVSS v3.1 Published 2023-10-19
Fix available
A fix is available. Upgrade to 2023.9.0 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Home assistant is an open source home automation. The Home Assistant login page allows users to use their local Home Assistant credentials and log in to another website that specifies the `redirect_uri` and `client_id` parameters. Although the `redirect_uri` validation typically ensures that it matches the `client_id` and the scheme represents either `http` or `https`, Home Assistant will fetch the `client_id` and check for `<link rel="redirect_uri" href="...">` HTML tags on the page. These URLs are not subjected to the same scheme validation and thus allow for arbitrary JavaScript execution on the Home Assistant administration page via usage of `javascript:` scheme URIs. This Cross-site Scripting (XSS) vulnerability can be executed on the Home Assistant frontend domain, which may be used for a full takeover of the Home Assistant account and installation. This issue has been addressed in version 2023.9.0 and all users are advised to upgrade. There are no known workarounds for this vulnerability.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Home Assistant's login page has an XSS vulnerability where it fetches client_id and checks for `<link rel="redirect_uri">` HTML tags on external pages. These discovered URLs lack the scheme validation applied to direct redirect_uri parameters, allowing javascript: scheme URIs to execute arbitrary JavaScript on the Home Assistant frontend domain for full account takeover.

MitigationUpgrade Home Assistant to version 2023.9.0 or later. No workarounds exist; this is a mandatory upgrade to remediate the critical XSS vulnerability.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Home AssistantApplication
Affected:< 2023.9.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify Home Assistant version
    Log into the Home Assistant web interface and check the version displayed on the Settings > About page, or check the homeassistant/const.py file in the installation directory if you have file system access.
    Affected if The installed version is earlier than 2023.9.0 (e.g., 2023.8.x, 2023.7.x, etc.)
  2. Verify login page is exposed
    Access the Home Assistant login page at your instance URL (e.g., https://your-instance.local:8123/auth/providers or the root URL) in a web browser.
    Affected if The login page loads and is accessible over the network, indicating the vulnerable endpoint is reachable.
  3. Check for external OAuth client_id configuration
    Inspect your Home Assistant configuration (configuration.yaml) and any custom auth provider configurations for client_id entries that reference external URLs, or check the Home Assistant authentication settings for configured OAuth clients.
    Affected if Custom OAuth or auth provider configurations with external client_id URLs are defined in your Home Assistant setup.

You are affected if your Home Assistant version is earlier than 2023.9.0 and the login page is accessible, regardless of whether external OAuth client configurations are present.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2023.9.0 or later
Fixed in 2023.9.0
Interim mitigation

Upgrade Home Assistant to version 2023.9.0 or later. No workarounds exist; this is a mandatory upgrade to remediate the critical XSS vulnerability.

Recommended fix High confidence

Home Assistant Core 2023.9.0 or later

  1. Access your Home Assistant instance and navigate to Settings > System > Overview
  2. Locate the Home Assistant Core section and click 'Update' to upgrade to the latest version
  3. Alternatively, access your Home Assistant host via SSH or terminal and run: ha core update
  4. Wait for the update to complete and verify the version is 2023.9.0 or later
  5. Confirm the login page now uses proper redirect_uri validation without javascript: scheme support
Caveat Review release notes for 2023.9.0 for any breaking changes in integrations or configuration; minor version updates typically have minimal impact

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Home Assistant Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing3.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,490
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-41895 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data