CVE-2023-41896
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 · uneditedHome assistant is an open source home automation. Whilst auditing the frontend code to identify hidden parameters, Cure53 detected `auth_callback=1`, which is leveraged by the WebSocket authentication logic in tandem with the `state` parameter. The state parameter contains the `hassUrl`, which is subsequently utilized to establish a WebSocket connection. This behavior permits an attacker to create a malicious Home Assistant link with a modified state parameter that forces the frontend to connect to an alternative WebSocket backend. Henceforth, the attacker can spoof any WebSocket responses and trigger cross site scripting (XSS). Since the XSS is executed on the actual Home Assistant frontend domain, it can connect to the real Home Assistant backend, which essentially represents a comprehensive takeover scenario. Permitting the site to be iframed by other origins, as discussed in GHSA-935v-rmg9-44mw, renders this exploit substantially covert since a malicious website can obfuscate the compromise strategy in the background. However, even without this, the attacker can still send the `auth_callback` link directly to the victim user. To mitigate this issue, Cure53 advises modifying the WebSocket code’s authentication flow. An optimal implementation in this regard would not trust the `hassUrl` passed in by a GET parameter. Cure53 must stipulate the significant time required of the Cure53 consultants to identify an XSS vector, despite holding full control over the WebSocket responses. In many areas, data from the WebSocket was properly sanitized, which hinders post-exploitation. The audit team eventually detected the `js_url` for custom panels, though generally, the frontend exhibited reasonable security hardening. This issue has been addressed in Home Assistant Core version 2023.8.0 and in the npm package home-assistant-js-websocket in version 8.2.0. 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 confidenceThis is a WebSocket authentication bypass vulnerability in Home Assistant where the `auth_callback=1` parameter combined with a manipulated `state` parameter (containing `hassUrl`) forces the frontend to connect to an attacker-controlled WebSocket backend instead of the legitimate one. The attacker can then spoof WebSocket responses to achieve XSS on the actual Home Assistant domain, enabling full account takeover since the malicious XSS can communicate with the real backend.
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< 2023.8.0< 8.2.0CVSS 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
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:L/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 checksWork through these to decide whether this CVE applies to you.
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Check Home Assistant Core version in the UINavigate to Settings > System > About in the Home Assistant web interface and look for the Core version number displayed.Affected if The displayed Core version is less than 2023.8.0 (for example, 2023.7.x, 2023.6.x, etc.)
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Check Home Assistant Core version via command lineRun the command `ha core info` if you have the Home Assistant CLI installed, or check the file `/config/.HA_VERSION` on your system.Affected if The reported version is below 2023.8.0
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Check frontend WebSocket library version (for developers)If you maintain a custom frontend integration or package, check your package.json or node_modules for the `home-assistant-js-websocket` package version.Affected if The installed version of home-assistant-js-websocket is below 8.2.0
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Identify if auth_callback parameter is being processedReview your Home Assistant logs and network traffic for any requests containing `auth_callback=1` combined with a `state` parameter, especially if the state contains an external or unexpected `hassUrl` value.Affected if Such requests are being processed by your instance (indicates potential exploitation attempt or vulnerable endpoint exposure)
You are affected if your Home Assistant Core version is below 2023.8.0 or your home-assistant-js-websocket library version is below 8.2.0, as either of these enables the authentication bypass vulnerability.
Generated from the published advisory. Verify against your own configuration.
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 · scoped8.2.02023.8.0
Upgrade to Home Assistant Core version 2023.8.0 or later, or update the npm package home-assistant-js-websocket to version 8.2.0 or later. There are no available workarounds.
Home Assistant Core 2023.8.0 or higher; home-assistant-js-websocket version 8.2.0 or higher
- 1. Back up your Home Assistant configuration before upgrading
- 2. For Home Assistant Core installations: Upgrade to version 2023.8.0 or later using your installation method (pip, container, OS, etc.)
- 3. For npm-based projects using the WebSocket library: Update the home-assistant-js-websocket package to version 8.2.0 or later by running 'npm update home-assistant-js-websocket' or 'npm install home-assistant-js-websocket@latest'
- 4. After upgrading, verify the WebSocket connection is functioning correctly
- 5. Check Home Assistant logs to confirm no errors related to authentication or WebSocket connections
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation6.0 h
- Implementation12.0 h
- Testing6.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2023-41896 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-41896 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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