Quick answer
Direct answer
Risk scores
| CVSS metric | What it means |
|---|---|
| Attack vector (AV:N) | Network: reachable remotely |
| Attack complexity (AC:L) | Low complexity |
| Privileges required (PR:N) | No privileges required |
| User interaction (UI:R) | A user must take an action |
| Scope (S:U) | Scope unchanged |
| Confidentiality (C:H) | High confidentiality impact |
| Integrity (I:H) | High integrity impact |
| Availability (A:N) | No availability impact |
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
About Sonarr
CVE-2026-30975 affects Sonarr, a product from Sonarr. Before acting, confirm where Sonarr runs in your estate, who owns it and whether it is reachable from the internet, because exposure decides real risk more than the score alone.
What the flaw is
In plain terms: Sonarr 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.
Based on its CVSS vector, the flaw can be reached over the network, needs no login, and relies on a user taking an action. Apply the vendor fix and confirm exposure on internet facing and business critical assets first.
Affected versions and timeline
| Field | Detail |
|---|---|
| Product | Sonarr |
| Affected versions | Sonarr before 4.0.16.2942 |
| Published | Mar 25, 2026 |
| Last modified | Jun 17, 2026 |
| Added to CISA KEV | Not listed |
| Assigning CNA | security-advisories@github.com |
How to detect it
- Inventory every instance of Sonarr and record the running version against the affected range above.
- Check external attack surface scans for internet facing instances of the component.
- Review logs on affected systems for unusual requests, errors or new processes around the vulnerable function.
- Confirm with an authenticated vulnerability scan once your scanner has a check for this CVE.
How to fix it
- Apply the fixed version of Sonarr named in the vendor advisory.
- If patching must wait, restrict network access to the affected service and put it behind authentication or a web application firewall rule.
- Rescan after the change to prove the exposure is gone, then close the ticket.
CTEM action plan
| CTEM stage | What to do for this CVE |
|---|---|
| Scope | Add every business service that depends on Sonarr to the current CTEM cycle. |
| Discover | Find all instances, including shadow and cloud deployments, and record versions and exposure. |
| Prioritize | Rank using EPSS and CVSS together with asset exposure and business impact. |
| Validate | Confirm the flaw is reachable and exploitable in your environment and that compensating controls work. |
| Mobilize | Assign the fix to the asset owner with a due date matched to the priority, then verify closure. |
CWE References
Technical References
Frequently asked questions
Related CVEs
Sonarr is a PVR for Usenet and BitTorrent users. In versions on the 4.x branch prior to 4.0.17.2950, an unauthenticated remote attacker can potentially read any file readable by the Sonarr process. These include application configuration files (containing API keys and database credentials), Windows system files, and any user-accessible files on the same drive This issue only impacts Windows systems; macOS and Linux are unaffected. Files returned from the API were not limited to the directory on disk they were intended to be served from. This problem has been patched in 4.0.17.2950 in the nightly/develop branch or 4.0.17.2952 for stable/main releases. It's possible to work around the issue by only hosting Sonarr on a secure internal network and accessing it via VPN, Tailscale or similar solution outside that network.
Authentication bypass by spoofing in Azure HorizonDB allows an unauthorized attacker to elevate privileges over a network.
In N2W before 4.3.2 and 4.4.0 before 4.4.1, improper validation of API request parameters enables remote code execution.
Spoofing issue in the WebAuthn component in Firefox for Android. This vulnerability was fixed in Firefox 148 and Thunderbird 148.
In N2W before 4.3.2 and 4.4.x before 4.4.1, there is potential remote code execution and account credentials theft because of a spoofing vulnerability.
FUXA is a web-based Process Visualization (SCADA/HMI/Dashboard) software. From 1.2.8 through 1.2.10, an authentication bypass vulnerability in FUXA allows an unauthenticated, remote attacker to execute arbitrary code on the server when the Node-RED plugin is enabled. This has been patched in FUXA version 1.2.11.
Earn your free CTEM certification.
Learn to scope, prioritize, validate and mobilize fixes for CVEs like CVE-2026-30975 with a free CTEM certification.
Beginner / Practitioner / Program Leader
Explore certifications