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Arbitrary file writes from unsanitized user input in cache file name

High
JelleZijlstra published GHSA-3936-cmfr-pm3m Mar 12, 2026

Package

pip psf/black (pip)

Affected versions

<26.3.1

Patched versions

26.3.1

Description

Impact

Black writes a cache file, the name of which is computed from various formatting options. The value of the --python-cell-magics option was placed in the filename without sanitization, which allowed an attacker who controls the value of this argument to write cache files to arbitrary file system locations.

Patches

Fixed in Black 26.3.1.

Workarounds

Do not allow untrusted user input into the value of the --python-cell-magics option.

Severity

High

CVE ID

CVE-2026-32274

Weaknesses

No CWEs

Credits