Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-30976 is a high-severity Path Traversal (CWE-22) vulnerability in Sonarr Sonarr. Its CVSS base score is 8.6 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked in the top 50% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-30976 is a path traversal vulnerability (CWE-22) in Sonarr, a PVR application for Usenet and BitTorrent users, affecting versions on the 4.x branch prior to 4.0.17.2950. The flaw occurs because files returned from the API are not restricted to the intended directory on disk, enabling an unauthenticated remote attacker to read any file accessible by the Sonarr process. This includes application configuration files containing API keys and database credentials, Windows system files, and any user-accessible files on the same drive. The issue is limited to Windows systems, with macOS and Linux unaffected.
An unauthenticated attacker with network access to a vulnerable Sonarr instance (CVSSv3.1 score of 8.6: AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N) can exploit this vulnerability remotely without privileges or user interaction. Successful exploitation grants high-impact confidentiality violations, allowing arbitrary file reads that could expose sensitive credentials, system information, or other data readable by the process, potentially leading to lateral movement or further compromise within the environment.
The Sonarr security advisory (GHSA-h393-v5hm-6h8f) and release notes detail patches in version 4.0.17.2950 for the nightly/develop branch and 4.0.17.2952 for stable/main releases. As a workaround, administrators should host Sonarr on a secure internal network and restrict external access via VPN, Tailscale, or similar solutions until patching is feasible.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-15992
Vulnerability Data
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.3.2
Mitigating Controls (NIST 800-53 r5) AI
Enforces the intended directory access authorizations that path traversal would otherwise bypass.
Input validation directly neutralizes special path elements before pathname construction occurs.
Least privilege reduces the impact of any unauthorized file access obtained via traversal.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.
PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.
Application security requirements include rules for safe file handling and canonicalization.
Secure architecture principles require least-privilege file access and directory isolation.
Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.
Security testing in development catches path traversal via static/dynamic analysis.
Information access restriction limits which files an application may read or write.