Race condition in tempfile.TemporaryDirectory cleanup allows deleting files outside the temporary directory

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-12345
StatePUBLISHED
AssignerPSF
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-09-29 18:17:14 UTC
Updated2026-10-26 01:17:15 UTC
DescriptionThe cleanup of tempfile.TemporaryDirectory is vulnerable to a race condition. An attacker who can modify the tree during cleanup can replace a directory with a symbolic link, causing files outside of the temporary directory to be deleted or have their permissions and file flags reset, with the privileges of the process performing the cleanup. Note that platforms where shutil.rmtree.avoids_symlink_attacks is false, remain affected, and file flags may still be reset outside of the tree on all platforms.

Risk And Classification

Primary CVSS: v4.0 5.9 MEDIUM from [email protected]

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/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: 0.001800000 probability, percentile 0.069470000 (date 2026-10-11)

Problem Types: CWE-59 | CWE-59 CWE-59 Improper Link Resolution Before File Access ('Link Following')

VersionSourceTypeScoreSeverityVector
4.0[email protected]Secondary5.9MEDIUMCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/C...
4.0CNACVSS5.9MEDIUMCVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS v4.0 Breakdown

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

CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/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 3.12.15 python Not specified
CNA Python Software Foundation CPython affected 3.13.0 3.13.18 python Not specified
CNA Python Software Foundation CPython affected 3.14.0 3.14.9 python Not specified
CNA Python Software Foundation CPython affected 3.15.0a1 3.15.0rc3 python Not specified

References

ReferenceSourceLinkTags
github.com/python/cpython/commit/c39b52d00b42200aaadff679e2fe3f1006d57c58 [email protected] github.com
github.com/python/cpython/commit/5c20517a4fc56683efe63a7751020db9573f538d [email protected] github.com
github.com/python/cpython/commit/06ef3d43fdaf4da97af12fa694b4886092c4b970 [email protected] github.com
github.com/python/cpython/commit/458e7134a5af7f86aee9d21b51cf499b41aa4420 [email protected] github.com
github.com/python/cpython/commit/58ed0259cae509a19138795df302fe60b544dc74 [email protected] github.com
github.com/python/cpython/pull/157580 [email protected] github.com
github.com/python/cpython/commit/0478b52788117db4b831b3efd648f56b777628aa [email protected] github.com
github.com/python/cpython/issues/157579 [email protected] github.com
github.com/python/cpython/commit/e1f3590f155c6d66007e958c98c9d69316551993 [email protected] github.com
www.openwall.com/lists/oss-security/2026/09/29/40 af854a3a-2127-422b-91ae-364da2661108 www.openwall.com
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: Bitshift (https://github.com/TheShiftedBit) (en)

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

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

© CVE.report 2026

Use of this information constitutes acceptance for use in an AS IS condition. There are NO warranties, implied or otherwise, with regard to this information or its use. Any use of this information is at the user's risk. It is the responsibility of user to evaluate the accuracy, completeness or usefulness of any information, opinion, advice or other content. EACH USER WILL BE SOLELY RESPONSIBLE FOR ANY consequences of his or her direct or indirect use of this web site. ALL WARRANTIES OF ANY KIND ARE EXPRESSLY DISCLAIMED. This site will NOT BE LIABLE FOR ANY DIRECT, INDIRECT or any other kind of loss.

CVE, CWE, and OVAL are registred trademarks of The MITRE Corporation and the authoritative source of CVE content is MITRE's CVE web site. This site includes MITRE data granted under the following license.

Free CVE JSON API cve.report/api

CVE.report and Source URL Uptime Status status.cve.report