CVE-2026-92355 in Octopus Server
Summary
by MITRE • 09/16/2026
In affected versions of Octopus Server, a user with permission to modify non built-in external feeds could exploit a path traversal flaw to overwrite arbitrary files on the server, which in some configurations could lead to remote code execution.
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Analysis
by VulDB Data Team • 09/16/2026
The vulnerability identified in Octopus Server represents a critical security failure rooted in improper validation of input data during file system operations. Specifically, this issue affects versions where users possess permissions to modify non-built-in external feeds. The core technical flaw is a path traversal vulnerability that allows an authenticated attacker with these specific privileges to manipulate the file paths used when saving or updating feed configurations. By injecting directory traversal sequences such as dot-dot-slash into the input fields associated with feed URLs or storage locations, the application fails to adequately sanitize or canonicalize the provided path before processing it. This lack of rigorous validation enables the attacker to break out of the intended sandboxed directory structure and write files to arbitrary locations on the server's file system.
The operational impact of this vulnerability is severe due to its potential escalation from simple data manipulation to complete system compromise. While the immediate effect involves overwriting arbitrary files, which could disrupt service availability or corrupt configuration settings, the most dangerous consequence arises in specific deployment configurations where Octopus Server has write access to directories containing executable scripts or web-deployable content. If an attacker can overwrite a file within such a directory with malicious code, they may achieve remote code execution on the host machine. This effectively grants the attacker full control over the server infrastructure running Octopus Server, allowing them to exfiltrate sensitive data, install backdoors, pivot to other systems on the network, or disrupt critical deployment pipelines managed by the platform.
From a classification perspective, this vulnerability aligns with CWE-22: Improper Limitation of a Pathname to a Restricted Directory, which describes flaws where software does not properly neutralize special elements within file paths that could resolve to unintended destinations. Furthermore, in the context of the MITRE ATT&CK framework, this exploit technique maps to T1059 Command and Scripting Interpreter if used for execution or potentially T1224 File Discovery combined with T1036 Masquerading depending on how the overwritten files are utilized by subsequent processes. The vulnerability highlights a common pitfall in web application development where trust is placed in user-supplied input without sufficient verification against expected file system boundaries, particularly when dealing with external integrations like feed sources that require dynamic path resolution.
Mitigation strategies must address both immediate remediation and long-term architectural improvements. The primary defense is to apply the vendor-provided patch or update Octopus Server to a version where this issue has been resolved through enhanced input validation and strict canonicalization of file paths before any disk operations are performed. Administrators should also enforce the principle of least privilege by ensuring that service accounts running Octopus Server have minimal necessary permissions on the underlying operating system, specifically restricting write access to directories containing executable code or sensitive configuration files. Additionally, implementing robust logging and monitoring for unusual file creation events in critical directories can aid in early detection of exploitation attempts. Regular security audits focusing on input validation patterns across all external feed integrations are recommended to prevent similar path traversal issues from emerging in other components of the application stack.