py7zr: Arbitrary File Write Vulnerability_CVE-2026-23879

8 / 10

HIGH

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H

Description

py7zr is a Python-based library and utility to support 7zip archive compression, decompression, encryption and decryption. Versions 1.1.2 and below contain an an arbitrary file write vulnerability, which allows symbolic links to be recreated outside the destination directory via crafted malicious symbolic link chains. When using extractall to extract an archive, the library restores these symbolic links, linking them to arbitrary directories on the host file system. During extraction, the program only checks the link arcname within the destination directory, but ignores the combined symlink path resolution. Attackers can exploit this vulnerability by constructing malicious archives, thereby bypassing the directory boundary restrictions implemented by the extractor. Subsequent extraction of regular files through these symbolic links can result in arbitrary file writes. This vulnerability may lead to remote code execution, privilege escalation, data corruption, or denial of service. This issue has been fixed in version 1.1.3.

Basic Information

ID CVE-2026-23879

Source GitHub_M

Published Jun 24, 2026 at 19:17

Affected Product

Vendor miurahr

Product py7zr

Version < 1.1.3

Affected Versions miurahr py7zr < 1.1.3

CWE Classification

CWE-59

References

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    "published": "2026-06-24T19:17:28.605Z",
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