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.
History

Thu, 25 Jun 2026 16:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'total'}, 'version': '2.0.3'}


Thu, 25 Jun 2026 12:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-22
References
Metrics threat_severity

None

threat_severity

Important


Wed, 24 Jun 2026 20:00:00 +0000

Type Values Removed Values Added
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.
Title py7zr: Arbitrary File Write Vulnerability
Weaknesses CWE-59
References
Metrics cvssV3_1

{'score': 8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2026-06-24T19:17:28.605Z

Updated: 2026-06-25T15:57:59.954Z

Reserved: 2026-01-16T21:02:02.900Z

Link: CVE-2026-23879

cve-icon Vulnrichment

Updated: 2026-06-25T15:57:09.537Z

cve-icon NVD

No data.

cve-icon Redhat

Severity : Important

Publid Date: 2026-06-24T19:17:28Z

Links: CVE-2026-23879 - Bugzilla