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CVE-2025-4138— Bypassing extraction filter to create symlinks to arbitrary targets outside extraction directory

Quick assessment

Affected
Python Software Foundation CPython
Exploitation
Public or AI PoC available; prioritize validation
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Python是Python基金会的一套开源的、面向对象的程序设计语言。该语言具有可扩展、支持模块和包、支持多种平台等特点。 Python 3.12及之后版本存在安全漏洞，该漏洞源于提取过滤器可被忽略，可能导致符号链接指向目标目录外和修改文件元数据。

CVSS 7.5 · High EPSS 1.39% · P71

Possible ATT&CK Techniques 1 AI

T1083 · File and Directory Discovery

Affected Version Matrix 6

VendorProduct Version RangeStatus
Python Software Foundation CPython < 3.9.23 affected
3.10.0< 3.10.18 affected
3.11.0< 3.11.13 affected
3.12.0< 3.12.11 affected
3.13.0< 3.13.4 affected
3.14.0a1< 3.14.0b3 affected
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I. Basic Information for CVE-2025-4138

Vulnerability Information
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Vulnerability Title
Bypassing extraction filter to create symlinks to arbitrary targets outside extraction directory
Source: CVE Program / CVE List V5
Vulnerability Description
Allows the extraction filter to be ignored, allowing symlink targets to point outside the destination directory, and the modification of some file metadata. You are affected by this vulnerability if using the tarfile module to extract untrusted tar archives using TarFile.extractall() or TarFile.extract() using the filter= parameter with a value of "data" or "tar". See the tarfile extraction filters documentation https://docs.python.org/3/library/tarfile.html#tarfile-extraction-filter  for more information. Note that for Python 3.14 or later the default value of filter= changed from "no filtering" to `"data", so if you are relying on this new default behavior then your usage is also affected. Note that none of these vulnerabilities significantly affect the installation of source distributions which are tar archives as source distributions already allow arbitrary code execution during the build process. However when evaluating source distributions it's important to avoid installing source distributions with suspicious links.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Source: CVE Program / CVE List V5
Vulnerability Type
对路径名的限制不恰当(路径遍历)
Source: CVE Program / CVE List V5
Vulnerability Title
Python 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Python是Python基金会的一套开源的、面向对象的程序设计语言。该语言具有可扩展、支持模块和包、支持多种平台等特点。 Python 3.12及之后版本存在安全漏洞，该漏洞源于提取过滤器可被忽略，可能导致符号链接指向目标目录外和修改文件元数据。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Python Software Foundation CPython 0 ~ 3.9.23 -

II. Public POCs for CVE-2025-4138

# POC Description Source Link Shenlong Link
1 CVE-2025-4138 / CVE-2025-4517 — Python tarfile PATH_MAX Symlink Filter Bypass https://github.com/DesertDemons/CVE-2025-4138-4517-POC POC Details
2 CVE-2025-4138 - Python Arbitrary file write outside extraction directory https://github.com/thefizzyfish/CVE-2025-4138_tarfile_filter_bypass POC Details
3 A Python script to generate a malicious tar archive that exploits CVE-2025-4138 / CVE-2025-4517. https://github.com/kyakei/CVE-2025-4138-poc POC Details
4 Tarfile module directory traversal vulnerability ( with overflow crossed Directory ) --> Lead to Privilege escalation https://github.com/localh0ste/CVE-2025-4138 POC Details
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III. Intelligence Information for CVE-2025-4138

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Patches & Fixes for CVE-2025-4138 (5)

Same Patch Batch · Python Software Foundation · 2025-06-03 · 5 CVEs total

CVE-2025-4517 9.4 CRITICAL Arbitrary writes via tarfile realpath overflow
CVE-2025-4330 7.5 HIGH Extraction filter bypass for linking outside extraction directory
CVE-2025-4435 7.5 HIGH Tarfile extracts filtered members when errorlevel=0
CVE-2024-12718 5.3 MEDIUM Bypass extraction filter to modify file metadata outside extraction directory

IV. Related Vulnerabilities

Same product: CPython
Same vendor: Python Software Foundation
Same weakness: CWE-22

V. Comments for CVE-2025-4138

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