Description
Black is the uncompromising Python code formatter. Starting in version 24.3.0 and prior to version 26.3.1, 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. Fixed in Black 26.3.1.
Affected products
python: black
References10
- github.com/psf/black/security/advisories/GHSA-3936-cmfr-pm3m Vendor Advisory
- github.com/psf/black/commit/4937fe6cf241139ddbfc16b0bdbb5b42279… Patch
- github.com/psf/black/pull/5038 Issue TrackingPatch
- access.redhat.com/errata/RHSA-2026:10184
- access.redhat.com/errata/RHSA-2026:13545
- access.redhat.com/errata/RHSA-2026:13553
- access.redhat.com/security/cve/CVE-2026-32274
- bugzilla.redhat.com/show_bug.cgi?id=2447111
- github.com/psf/black/commit/ed770ba4dd50c419148a0fca2b43937a744…
- github.com/psf/black/pull/4176
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N - CVSS 4.0
-
8.7
HIGH
Score source: CNA
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/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 — exploit probability
- 1% percentile: 53 · as of 12 November 2026
- CWE
- CWE-22
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.