tarfile extraction filter bypass allows creation of directories outside the destination

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-19672
StatePUBLISHED
AssignerPSF
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-19 16:17:06 UTC
Updated2026-08-28 21:16:15 UTC
DescriptionThe tarfile module's tar and data extraction filters created directories outside the destination for members whose name leaves the destination and returns to it, such as ../evil/../dest/sub/file. The containment check used the resolved path, but intermediate directories were created from the name as given. Only empty directories are created outside the destination. Member contents are still extracted inside it. To return to the destination the member's name must contain the destination directory's own final component, so extraction into a secure randomised directory is not affected. This affects POSIX platforms only. On Windows, .. components are collapsed before the path reaches the filesystem, so the directories outside the destination are never created.

Risk And Classification

Primary CVSS: v4.0 6.3 MEDIUM from [email protected]

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS: 0.004090000 probability, percentile 0.339480000 (date 2026-08-31)

Problem Types: CWE-22 | CWE-22 CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary6.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/C...
4.0CNACVSS6.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
None
Integrity
None
Availability
None
Sub Conf.
None
Sub Integrity
Low
Sub Availability
None

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Python Software Foundation CPython affected 3.16.0 python Not specified

References

ReferenceSourceLinkTags
www.openwall.com/lists/oss-security/2026/08/25/10 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
github.com/python/cpython/pull/156000 [email protected] github.com
mail.python.org/archives/list/[email protected]/thread/J2WT2ALRWEX... [email protected] mail.python.org
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Lohinth (https://github.com/l0h1nth) (en)

CNA: Stan Ulbrych (https://github.com/StanFromIreland) (en)

CNA: Petr Viktorin (https://github.com/encukou) (en)

CNA: Ethan Furman (https://github.com/ethanfurman) (en)

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