CVE-2026-79824 in NonStop Python
Summary
by MITRE • 10/15/2026
A directory traversal vulnerability in HPE NonStop Python 3.x could allow attackers to overwrite arbitrary files via a .. (dot dot) sequence in filenames in a TAR archive.
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Analysis
by VulDB Data Team • 10/15/2026
The identified security flaw resides within the HPE NonStop Python 3.x runtime environment, specifically affecting its handling of archived file structures during extraction processes. This vulnerability is classified as a directory traversal issue, which fundamentally stems from insufficient validation of path components contained within compressed archives. When the software processes TAR files, it fails to adequately sanitize or normalize filenames before writing them to the local filesystem. An attacker can exploit this lack of input validation by crafting a malicious archive that contains file entries with paths prefixed by double-dot sequences, such as .., which are standard indicators for moving up one directory level in hierarchical file systems. By carefully constructing these path strings, an adversary can manipulate the destination directory where files are extracted, effectively bypassing intended sandboxing or isolation boundaries designed to keep application data within specific directories.
The technical mechanism of this exploit relies on the operating system's interpretation of relative paths during write operations. When a TAR archive is processed, each entry specifies both its internal path and the target location for extraction. If the software does not resolve these paths against a secure base directory or strip out traversal sequences before performing file I/O operations, it will follow the instructions literally. Consequently, instead of placing files within the expected application folder, the system writes them to arbitrary locations on the disk determined by the attacker's input. This capability allows for the overwriting of critical system configuration files, executable binaries, or other sensitive data stored outside the intended scope. The severity is heightened because TAR archives are commonly used in software distribution and deployment pipelines, meaning this vulnerability could be triggered during routine updates or automated build processes if untrusted sources are involved.
From an operational perspective, the impact of this directory traversal vulnerability extends beyond simple file overwriting to potential remote code execution and privilege escalation. If an attacker can overwrite a script that is executed with elevated privileges by the Python runtime or the underlying operating system user account, they may achieve arbitrary command execution on the host machine. This could lead to a complete compromise of the HPE NonStop server's integrity and availability. Furthermore, overwriting configuration files might allow for persistent access mechanisms or disruption of services running on the platform. The vulnerability aligns with Common Weakness Enumeration CWE-22, which defines Improper Limitation of a Pathname to a Restricted Directory. This classification highlights that the software does not enforce strict boundaries on file system paths provided by external inputs, allowing actions outside the restricted directory context.
To mitigate this risk, immediate remediation should focus on updating HPE NonStop Python 3.x to versions where the TAR extraction logic has been hardened against path traversal attacks. Developers and administrators must ensure that all archive processing functions utilize canonicalization techniques to resolve paths fully before writing files, ensuring they remain within designated safe directories. Additionally, implementing strict allow-listing for file extensions and validating that resolved paths do not escape the intended root directory are essential defensive measures. In environments where patching is delayed, input validation at the application layer should be enforced to reject any archive entries containing relative path components or traversal sequences. Monitoring logs for unusual file write operations in system directories can also aid in early detection of exploitation attempts. This vulnerability underscores the critical importance of secure coding practices when handling untrusted compressed data, particularly in enterprise-grade environments like HPE NonStop where reliability and security are paramount. The mitigation strategy should also include regular audits of third-party libraries used for archive manipulation to ensure they adhere to current industry standards such as those outlined by OWASP regarding file upload and extraction safety.