Race condition in tempfile.TemporaryDirectory cleanup allows deleting files outside the temporary directory (CVE-2026-12345) | HOL Guard CVE

Medium · CVSS 5.9CVE-2026-12345

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

Answer in brief

CVE-2026-12345 records a Medium severity (CVSS 5.9) vulnerability in Race condition in tempfile.TemporaryDirectory cleanup allows deleting files outside the temporary directory. The current sources do not mark it as known exploited. The current feed maps Python Software Foundation/CPython (generic), Python Software Foundation/CPython (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Sep 29, 2026Updated Sep 29, 2026Source checked Sep 29, 2026First seen by HOL Sep 29, 2026Material review Sep 29, 2026

Upstream Advisory

Key facts

Risk: Medium · CVSS 5.9
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 5.9. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Python Software Foundation/CPython (generic), Python Software Foundation/CPython (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Python Software Foundation/CPythongeneric	>=0 <3.16.0	3.16.0
Python Software Foundation/CPythongeneric	>=0 <3.15.0	3.15.0

Recommended response

Check inventory. Check lockfiles and deployed manifests for Python Software Foundation/CPython, Python Software Foundation/CPython.
Review the reported fix. Update Python Software Foundation/CPython to 3.16.0; Python Software Foundation/CPython to 3.15.0 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Sep 29, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Sep 29, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Sep 29, 2026

Sources and claim methodology

Upstream source description

The 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.

Quoted source text, attributed separately from HOL analysis.