CVE-2025-8869 in pip
Summary
by MITRE • 09/24/2025
When extracting a tar archive pip may not check symbolic links point into the extraction directory if the tarfile module doesn't implement PEP 706. Note that upgrading pip to a "fixed" version for this vulnerability doesn't fix all known vulnerabilities that are remediated by using a Python version that implements PEP 706.
Note that this is a vulnerability in pip's fallback implementation of tar extraction for Python versions that don't implement PEP 706 and therefore are not secure to all vulnerabilities in the Python 'tarfile' module. If you're using a Python version that implements PEP 706 then pip doesn't use the "vulnerable" fallback code.
Mitigations include upgrading to a version of pip that includes the fix, upgrading to a Python version that implements PEP 706 (Python >=3.9.17, >=3.10.12, >=3.11.4, or >=3.12), applying the linked patch, or inspecting source distributions (sdists) before installation as is already a best-practice.
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Analysis
by VulDB Data Team • 11/03/2025
The vulnerability identified as CVE-2025-8869 represents a critical security flaw in pip's handling of tar archive extraction operations, specifically affecting Python environments that lack support for PEP 706 implementation. This weakness manifests when pip attempts to extract tar archives and fails to properly validate symbolic link destinations, potentially allowing malicious actors to create symbolic links that point outside the intended extraction directory. The vulnerability exists within pip's fallback implementation designed for older Python versions that do not natively support PEP 706, creating a window of opportunity for path traversal attacks and arbitrary file system modifications.
The technical core of this vulnerability lies in the absence of proper boundary checking for symbolic links during tar extraction processes. When Python versions prior to the specified PEP 706 implementations are used, pip resorts to its legacy extraction methods that do not adequately verify whether symbolic links within tar archives reference paths outside the designated extraction target. This creates a scenario where an attacker could craft a malicious tar archive containing symbolic links pointing to sensitive system locations, potentially leading to privilege escalation, data exfiltration, or system compromise. The vulnerability directly relates to CWE-22 Path Traversal and CWE-59 Unsafe Handling of Path Names, as it allows for improper path validation during archive extraction operations.
The operational impact of this vulnerability extends beyond simple path traversal concerns, as it fundamentally undermines the security model of pip's package installation process. When exploited, this vulnerability can enable attackers to install malicious code in unintended locations, modify system files, or gain unauthorized access to sensitive directories. The risk is particularly elevated in environments where pip is used with elevated privileges or in automated deployment scenarios. The vulnerability's remediation is complex because it requires addressing both the pip implementation and the underlying Python runtime capabilities, as upgrading pip alone does not resolve all potential attack vectors that exist within the Python tarfile module itself.
Effective mitigation strategies must address multiple layers of the vulnerability chain. The primary recommended approach involves upgrading to Python versions that properly implement PEP 706, specifically versions 3.9.17, 3.10.12, 3.11.4, or 3.12 and above, which provide native secure tar extraction capabilities. Additionally, organizations should upgrade to pip versions that include the specific fix for this vulnerability, ensuring that the fallback implementation is properly patched. Alternative mitigation approaches include applying the vendor-provided patch, implementing strict source distribution inspection protocols, and maintaining awareness of the ATT&CK technique T1195.002 for Archive via SymLinks, which specifically addresses the exploitation of symbolic link vulnerabilities in archive extraction processes. Organizations should also consider implementing network-level controls and monitoring for suspicious tar archive extraction activities to detect potential exploitation attempts.