Raw vector
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:XSummary
CVE-2026-32274 is a high-severity Path Traversal (CWE-22) vulnerability in Python Black. Its CVSS base score is 8.7 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 47th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SI-10 (Information Input Validation) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-32274 affects the Black Python code formatter in versions prior to 26.3.1. The vulnerability arises because Black constructs cache filenames from various formatting options, including the --python-cell-magics argument, without sanitizing its value. This leads to a path traversal issue (CWE-22), enabling cache files to be written to arbitrary filesystem locations. The CVSS v3.1 base score is 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N), highlighting high integrity impact with no confidentiality or availability effects.
An attacker who controls the --python-cell-magics option value—such as through malicious input in environments where Black is invoked programmatically or via scripts processing untrusted data—can exploit this remotely with low complexity and no privileges or user interaction required. Successful exploitation allows writing cache files to unintended locations, potentially overwriting files and compromising system integrity based on the executing process's permissions.
The vulnerability was addressed in Black 26.3.1, as detailed in the GitHub security advisory GHSA-3936-cmfr-pm3m, fixing commit 4937fe6cf241139ddbfc16b0bdbb5b422798909d, pull request #5038, and release notes. Mitigation involves upgrading to Black 26.3.1 or later to ensure proper sanitization of the option value in cache filenames.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-11698
Vulnerability Data
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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.3.2
Mitigating Controls (NIST 800-53 r5) AI
Enforces the intended directory access authorizations that path traversal would otherwise bypass.
Input validation directly neutralizes special path elements before pathname construction occurs.
Least privilege reduces the impact of any unauthorized file access obtained via traversal.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Patching/maintenance can remediate known path-traversal flaws in deployed software (partial prevention of exploitability) but does nothing to stop the coding defect from being introduced in the first place.
PR.AA-05 defines and reviews access policies but does not address code-level pathname neutralization, so neither direction prevents CWE-22.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing in development catches path traversal via static/dynamic analysis.
Secure SDLC mandates input validation and path sanitization that directly prevent path traversal.
Application security requirements include rules for safe file handling and canonicalization.
Secure architecture principles require least-privilege file access and directory isolation.
Secure coding standards explicitly forbid unsafe path construction and mandate safe APIs.
Information access restriction limits which files an application may read or write.