CVE-2021-3152
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 before 2021.1.3 does not have a protection layer that can help to prevent directory-traversal attacks against custom integrations. NOTE: the vendor's perspective is that the vulnerability itself is in custom integrations written by third parties, not in Home Assistant; however, Home Assistant does have a security update that is worthwhile in addressing this situation
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 confidenceHome Assistant before version 2021.1.3 lacks a protection layer to prevent directory-traversal attacks targeting custom integrations. Attackers could potentially use path traversal sequences in custom integration file handling to access files outside intended directories.
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< 2021.1.3CVSS 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
- None
- Scope
- Unchanged
- Confidentiality
- Low
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
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 version via web UILog into the Home Assistant web interface, navigate to Configuration (gear icon) > Info. The version is displayed at the top of the page.Affected if The displayed version number is lower than 2021.1.3 (for example, 2021.1.2, 2021.1.1, 2020.12.x, etc.)
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Check Home Assistant version via command lineIf you have SSH access to the Home Assistant host, run the command appropriate to your installation type: for Home Assistant OS run `ha core version`, for Docker run `docker ps` to find the container and check its version, or check the file /config/.HAVERSION if accessible.Affected if The returned version is below 2021.1.3.
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Check for custom integrations in the UIIn the Home Assistant web interface, navigate to Configuration > Integrations. Look for any integrations that were installed manually or from the community (often listed with non-standard sources or custom names).Affected if Any custom or third-party integrations are installed and listed in this page.
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Check for custom_components directoryIf you have file system access to the Home Assistant configuration directory, check for the presence of a /config/custom_components/ folder. This directory contains custom integration code.Affected if The custom_components directory exists and contains subdirectories with integration code.
You are affected if your Home Assistant version is before 2021.1.3 AND you have custom integrations installed (either listed in the Integrations page or with files in the custom_components directory).
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.
From vendor data2021.1.3
Update Home Assistant to version 2021.1.3 or later to apply the security update; custom integration developers should also implement proper path validation in their code.
- Consultation1.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-3152 — 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-2021-3152 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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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.
- 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
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