CVE-2025-22873 is a relative path traversal vulnerability identified in the Go standard library's os package, specifically affecting the os.Root.Open function. The flaw allows an attacker to open the parent directory of a defined root directory by providing a filename that ends with "../". This bypasses intended directory restrictions by permitting access to the immediate parent directory, although it does not allow traversal beyond that or access to files within the parent directory. The vulnerability arises because the path sanitization logic in the os package does not correctly handle trailing "../" sequences, enabling this limited directory escape. The affected versions include all Go releases up to 1.24.0-0. No CVSS score has been assigned yet, and no known exploits have been reported in the wild. The vulnerability could be exploited in scenarios where Go applications use os.Root.Open to restrict file system access, such as sandboxed environments or containerized applications. Attackers with the ability to influence file paths passed to this function could leverage this flaw to gain unintended directory visibility, potentially exposing sensitive directory metadata or configuration files located in the parent directory. However, since the traversal is limited to the immediate parent directory and does not allow file reads within it, the impact is somewhat constrained. The vulnerability highlights the importance of rigorous path validation and sandboxing in file system operations within Go applications.

For European organizations, the impact of CVE-2025-22873 depends largely on the extent to which Go-based applications are used to enforce file system boundaries or sandboxing. Organizations that deploy Go applications in cloud-native environments, microservices, or containerized platforms may be at risk if these applications rely on os.Root.Open for directory access restrictions. The vulnerability could lead to unauthorized disclosure of directory contents or metadata in the parent directory, potentially exposing sensitive configuration or operational data. While the traversal does not allow access to files within the parent directory, knowledge of directory structure or metadata can aid attackers in further reconnaissance or targeted attacks. This could impact confidentiality and integrity of systems, especially in regulated industries such as finance, healthcare, or critical infrastructure sectors prevalent in Europe. The lack of known exploits reduces immediate risk, but the vulnerability could be leveraged in targeted attacks once weaponized. Additionally, organizations relying on Go for internal tooling or customer-facing applications should assess exposure to this flaw to prevent privilege escalation or sandbox escape scenarios.

1. Upgrade to a fixed version of the Go standard library once a patch is released beyond version 1.24.0-0 to ensure the vulnerability is addressed at the source. 2. Implement strict input validation and sanitization on all file path inputs, explicitly disallowing trailing "../" sequences or other path traversal patterns before passing them to os.Root.Open or similar functions. 3. Employ additional sandboxing or containerization layers that enforce file system access controls independently of application logic, limiting the impact of any directory traversal. 4. Conduct code reviews and static analysis focused on file system access patterns in Go applications to identify and remediate unsafe usage of os.Root.Open or related APIs. 5. Monitor application logs for unusual file access patterns or attempts to use directory traversal sequences in file paths. 6. Educate developers about secure file handling practices in Go, emphasizing the risks of path traversal and the importance of defense-in-depth. 7. For critical environments, consider runtime application self-protection (RASP) or host-based intrusion detection systems to detect and block suspicious file system operations.