CVE-2026-30975
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 · uneditedSonarr is a PVR for Usenet and BitTorrent users. Versions prior to 4.0.16.2942 have an authentication bypass that affected users that had disabled authentication for local addresses (Authentication Required set to: `Disabled for Local Addresses`) without a reverse proxy running in front of Sonarr that didn't not pass through the invalid header. Patches are available in version 4.0.16.2942 in the nightly/develop branch and version 4.0.16.2944 for stable/main releases. Some workarounds are available. Make sure Sonarr's Authentication Required setting is set to `Enabled`, run Sonarr behind a reverse proxy, and/or do not expose Sonarr directly to the internet and instead rely on accessing it through a VPN, Tailscale or a similar solution.
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 confidenceSonarr versions prior to 4.0.16.2942 contain an authentication bypass vulnerability where users who configured 'Disabled for Local Addresses' can be bypassed if no reverse proxy is present or the proxy doesn't filter invalid headers, allowing unauthenticated remote attackers to access the application.
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< 4.0.16.2942CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/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 Sonarr versionAccess the Sonarr UI and navigate to System > About, or query the API at /api/v3/system/status to retrieve the 'version' fieldAffected if Version is below 4.0.16.2942
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Verify Authentication Required settingGo to Settings > Security > Authentication in the Sonarr UI, or inspect the config.xml file in the Sonarr app data directory for the 'AuthenticationMethod' valueAffected if Authentication Required is set to 'Disabled for Local Addresses' or equivalent disabled-for-local configuration
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Confirm direct internet exposureCheck whether Sonarr is listening on a public IP or is directly accessible from the internet without a reverse proxy in front of it. Review your firewall rules, router port forwards, and reverse proxy configuration.Affected if Sonarr is directly exposed to the internet (no reverse proxy filtering headers)
You are affected if Sonarr version is below 4.0.16.2942, the Authentication Required setting is configured as 'Disabled for Local Addresses', and Sonarr is directly accessible without a reverse proxy filtering requests.
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 · scoped4.0.16.2942
Enable Authentication Required (set to 'Enabled' rather than 'Disabled for Local Addresses'), deploy a proper reverse proxy, or ensure Sonarr is only accessible via VPN/Tailscale rather than directly exposed to the internet.
Sonarr version 4.0.16.2944 (stable) or 4.0.16.2942 (nightly/develop)
- 1. Back up your current Sonarr configuration and database before upgrading.
- 2. Upgrade Sonarr to version 4.0.16.2944 (stable/main release) or 4.0.16.2942 (nightly/develop branch).
- 3. After upgrading, verify the Authentication Required setting in Sonarr is set to 'Enabled' rather than 'Disabled for Local Addresses'.
- 4. If you must keep 'Disabled for Local Addresses', ensure a properly configured reverse proxy is in front of Sonarr that does not pass invalid authentication headers.
- 5. Ensure Sonarr is not directly exposed to the internet; access it through a VPN, Tailscale, or similar secure method instead.
- 6. Test the authentication is working correctly after the upgrade.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-30975 — 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-2026-30975 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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- 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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