CVE-2026-11940 | tarfile.extractall() with the 'data' or 'tar' filter could … | CVSS 7.8 HIGH

Description

tarfile.extractall() with the 'data' or 'tar' filter could be bypassed by a crafted archive where a hardlink references a symlink stored at a deeper name than the hardlink itself. The extraction fallback validated the symlink at it's archived location but recreated it at the hardlink's shallower path, letting a relative target the filter judged contained escape the destination directory. This allowed a malicious tar archive to create a symlink pointing outside the destination, enabling out-of-destination file reads or writes. This was an incomplete fix of CVE-2025-4330.

Metadata

CVE ID: CVE-2026-11940
State: PUBLISHED
Assigner: PSF
Reserved: 2026-06-10 19:50 UTC
Published: 2026-06-23 16:04 UTC
Last updated: 2026-06-23 17:57 UTC
Primary CWE: CWE-22
CWE-22
Vendor / Product: Python Software Foundation / CPython
Sources: cve.org · NVD

Severity & Metrics

7.8 HIGH CVSS 4.0

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

SSVC — CISA Coordinator

Exploitation: none
Automatable: yes
Tech. Impact: partial

Affected products (1)

Vendor	Product	Platform	Versions
Python Software Foundation	CPython	—	0 < 3.15.0

Weakness (CWE)

CWE	Source	Description
CWE-22	cna	CWE-22
CWE-59	cna	CWE-59

CVSS scores (1)

Score	Severity	Version	Source	Vector
7.8	HIGH	4.0	cna	CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:H/SI:H/SA:N

References (7)