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:N) | No user interaction |
| Scope (S:C) | Scope changed: impact spreads beyond the component |
| Confidentiality (C:H) | High confidentiality impact |
| Integrity (I:N) | No integrity impact |
| Availability (A:N) | No availability impact |
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
About Sonarr
CVE-2026-30976 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. 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.
The weakness class is Path Traversal. An attacker can reach files outside the intended folder by tampering with a file path.
Based on its CVSS vector, the flaw can be reached over the network, needs no login, and needs no user interaction. 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 from 4.0.0.741 before 4.0.17.2950 |
| 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
- CWE-22: Path Traversal More CVEs with this weakness
Technical References
Frequently asked questions
Related CVEs
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.
Mesop is a Python-based UI framework that allows users to build web applications. Versions 1.2.2 and below contain a Path Traversal vulnerability that allows any user supplying an untrusted state_token through the UI stream payload to arbitrarily target files on the disk under the standard file-based runtime backend. This can result in application denial of service (via crash loops when reading non-msgpack target files as configurations), or arbitrary file manipulation. This vulnerability heavily exposes systems hosted utilizing FileStateSessionBackend. Unauthorized malicious actors could interact with arbitrary payloads overwriting or explicitly removing underlying service resources natively outside the application bounds. This issue has been fixed in version 1.2.3.
Vociferous provides cross-platform, offline speech-to-text with local AI refinement. Prior to 4.4.2, the vulnerability exists in src/api/system.py within the export_file route. The application accepts a JSON payload containing a filename and content. While the developer intended for a native UI dialog to handle the file path, the API does not validate the filename string before it is processed by the backends filesystem logic. Because the API is unauthenticated and the CORS configuration in app.py is overly permissive (allow_origins=["*"] or allowing localhost), an external attacker can bypass the UI entirely. By using directory traversal sequences (../), an attacker can force the app to write arbitrary data to any location accessible by the current user's permissions. This vulnerability is fixed in 4.4.2.
Erugo is a self-hosted file-sharing platform. In versions up to and including 0.2.14, an authenticated low-privileged user can upload arbitrary files to any specified location due to insufficient validation of user‑supplied paths when creating shares. By specifying a writable path within the public web root, an attacker can upload and execute arbitrary code on the server, resulting in remote code execution (RCE). This vulnerability allows a low-privileged user to fully compromise the affected Erugo instance. Version 0.2.15 fixes the issue.
Arbitrary File Write via Path Traversal upload to Remote Code Execution in SeppMail User Web Interface. The affected feature is the large file transfer (LFT). This issue affects SeppMail: 15.0.2.1 and before
A path traversal vulnerability exists in the `extract_archive_to_dir` function within the `mlflow/pyfunc/dbconnect_artifact_cache.py` file of the mlflow/mlflow repository. This vulnerability, present in versions before v3.7.0, arises due to the lack of validation of tar member paths during extraction. An attacker with control over the tar.gz file can exploit this issue to overwrite arbitrary files or gain elevated privileges, potentially escaping the sandbox directory in multi-tenant or shared cluster environments.
Earn your free CTEM certification.
Learn to scope, prioritize, validate and mobilize fixes for CVEs like CVE-2026-30976 with a free CTEM certification.
Beginner / Practitioner / Program Leader
Explore certifications