Black: Arbitrary file writes from unsanitized user input in cache file name (psf black)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.65 % · percentile 51 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Modified
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.
Weaknesses (CWE)
- CWE-22 — Improper Limitation of a Pathname to a Restricted Directory
References
- https://github.com/psf/black/security/advisories/GHSA-3936-cmfr-pm3m
- https://github.com/psf/black/pull/4176
- https://github.com/psf/black/pull/5038
- https://github.com/psf/black/commit/4937fe6cf241139ddbfc16b0bdbb5b422798909d
- https://github.com/psf/black/commit/ed770ba4dd50c419148a0fca2b43937a7447e1f9
- https://access.redhat.com/errata/RHSA-2026:10184
- https://access.redhat.com/errata/RHSA-2026:13545
- https://access.redhat.com/errata/RHSA-2026:13553
- https://access.redhat.com/security/cve/CVE-2026-32274
- https://bugzilla.redhat.com/show_bug.cgi?id=2447111
- https://github.com/psf/black/releases/tag/26.3.1
- https://github.com/pypa/advisory-database/tree/main/vulns/black/PYSEC-2026-2121.yaml
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-32274.json
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 4.0 | HIGH 8.7 | 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 | GitHub_M |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N | redhat-SADP |
| CVSS 4.0 | HIGH 8.7 | 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 | NVD · security-advisories@github.com (Secondary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N | NVD · nvd@nist.gov (Primary) |
| CVSS 3.1 | HIGH 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
Advisories
- GHSA-3936-cmfr-pm3m — Black: Arbitrary file writes from unsanitized user input in cache file name
- PYSEC-2026-2121 — Black is the uncompromising Python code formatter. Prior to 26.3.1, Black writes a cache file, the name of which is computed from various formatting options. Th
European references
- ENISA EUVD · EUVD-2026-11698
- GCVE · GCVE-0-2026-32274
CERT-FR advisories
- CERTFR-2026-AVI-0556 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:python:black:*:*:*:*:*:python:*:*< 26.3.1
Affected products
| Product | Versions |
|---|---|
| psf · black | affected >= 24.3.0, < 26.3.1 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |