2

CVSS Score

4.0

-

CVSS Score

Basic Information

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CVE-2026-1703

CVE-2026-1703: Limited path traversal when installing wheel archives

When pip is installing and extracting a maliciously crafted wheel archive, files may be extracted outside the installation directory. The path traversal is limited to prefixes of the installation directory, thus isn't able to inject or overwrite executable files in typical situations.

(GitHub Advisory)

Miggo Vulnerability Database

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CVE-2026-1703

CVE-2026-1703:

2

CVSS Score

4.0

-

CVSS Score

Basic Information

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Technical Details

Package Name	Ecosystem	Vulnerable Versions	First Patched Version
pip	pip	< 26.0	26.0

Technical Details

Vulnerability Intelligence
Miggo AI

Root Cause Analysis

The security vulnerability is a path traversal issue in pip's unpacking logic. The root cause is the use of os.path.commonprefix in the is_within_directory function located in src/pip/_internal/utils/unpacking.py. This function is supposed to ensure that files from an archive are extracted only within the designated target directory. However, os.path.commonprefix performs a simple string prefix match, which is insufficient for path validation. An attacker can craft a filename that shares a common prefix with the target directory but uses path traversal elements (like ..) or similar-looking directory names to escape the intended directory. The patch addresses this by replacing os.path.commonprefix with os.path.commonpath, which is the correct and more secure way to determine if a path is a sub-path of another, as it operates on path components rather than raw strings. Any runtime profile during a malicious package installation would show calls to is_within_directory as part of the file extraction process.

Vulnerable functions

is_within_directory

src/pip/_internal/utils/unpacking.py

The function `is_within_directory` used `os.path.commonprefix` to validate file paths during extraction. This function is vulnerable to path traversal attacks because it compares paths character by character, which can be bypassed with carefully crafted filenames. An attacker could create a malicious wheel file that, when installed, would write files outside of the intended installation directory. The patch replaces the insecure `os.path.commonprefix` with `os.path.commonpath`, which correctly handles path comparisons.

Vulnerability Intelligence
Miggo AI

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WAF Protection Rules

WAF Rule

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Reasoning

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