CVE-2026-62965 in SABnzbd
Summary
by MITRE • 10/30/2026
SABnzbd is an open source automated Usenet download tool. Prior to 5.1.0Beta3, orphan-job management in `sabnzbd/api.py` accepts the user-controlled `value` parameter without path confinement before `os.path.join()` with `download_dir`. An absolute path discards that base directory. An attacker with a valid API key can invoke `mode=status` with `name=delete_orphan` to reach `_api_delete_orphan` and `remove_all()` in `sabnzbd/filesystem.py`, which uses `shutil.rmtree()` for recursive deletion. The advisory also identifies `_api_add_orphan` and `_api_delete_all_orphan` as affected by the path-validation issue, while its concrete arbitrary-deletion trace is through `_api_delete_orphan`. The API key is stored in plaintext in `sabnzbd.ini`. The attacker can delete files or directories writable by the SABnzbd process, including configuration, queue data, and downloads, but system files outside the regular user's ownership are not affected. This issue is fixed in version 5.1.0Beta3.
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Analysis
by VulDB Data Team • 10/30/2026
SABnzbd serves as a widely deployed open-source automated Usenet download manager that facilitates the retrieval of binary content from newsgroups. A critical security vulnerability exists within versions prior to 5.1.0Beta3, specifically involving the orphan-job management functionality exposed through its application programming interface. The core technical flaw resides in the `sabnzbd/api.py` module, where user-controlled input parameters are processed with insufficient validation before being integrated into file system operations. Specifically, when handling requests related to managing orphaned jobs, the software accepts a value parameter that is concatenated with a base download directory path using standard library functions without enforcing strict path confinement rules. This lack of rigorous input sanitization creates a classic path traversal condition where an attacker can manipulate the resulting file path by supplying absolute paths rather than relative ones.
The operational impact of this vulnerability allows for arbitrary file and directory deletion, which falls under the Common Weakness Enumeration category CWE-22: Improper Limitation of a Pathname to a Restricted Directory. When an authenticated user invokes the `mode=status` endpoint with the specific action parameter set to `delete_orphan`, the request triggers the `_api_delete_orphan` function in conjunction with the `remove_all()` routine located in `sabnzbd/filesystem.py`. This sequence ultimately calls upon Python's `shutil.rmtree()` method, which performs recursive deletion of directories and their contents. Because the path validation logic fails to reject absolute paths or properly resolve symbolic links before execution, an attacker can bypass the intended sandboxing mechanism that restricts operations to the designated download directory. Consequently, this leads to CWE-73: External Control of File Name or Path, enabling destructive actions beyond the scope of normal application behavior.
The severity of this issue is significantly amplified by the authentication model employed by SABnzbd. The API key required to access these endpoints is stored in plaintext within the `sabnzbd.ini` configuration file. This storage practice means that any individual with read access to the configuration file, or who has compromised credentials through other vectors such as credential stuffing or local privilege escalation on a shared system, can obtain valid authentication tokens. Once an attacker possesses this key, they are not required to exploit complex injection techniques; instead, they simply need to craft API requests targeting the vulnerable endpoints `_api_add_orphan`, `_api_delete_all_orphan`, and primarily `_api_delete_orphan`. The ability to delete files or directories writable by the SABnzbd process includes critical operational data such as configuration settings, queue metadata, and partially downloaded content. While system-level files outside the ownership of the regular user running the application remain protected due operating system permissions, the loss of application-specific data can result in complete service disruption and significant data integrity issues for the end-user.
From a threat intelligence perspective, this vulnerability aligns with ATT&CK technique T1485: Data Destruction, where an adversary aims to disrupt availability by destroying or encrypting data on local systems. The exploitation path is straightforward once initial access to the API key is achieved, highlighting the importance of defense-in-depth strategies even for internal-facing services. Mitigation efforts must prioritize immediate upgrading to version 5.1.0Beta3 or later, where the developers have implemented proper path confinement checks to ensure that all file operations remain strictly within the intended base directory regardless of input content. Additionally, organizations should review their configuration management practices by ensuring API keys are stored securely using environment variables or encrypted storage mechanisms rather than plaintext files. Regular auditing of access controls and limiting network exposure of administrative interfaces further reduces the attack surface associated with such authentication-dependent vulnerabilities.