Is CVE-2026-31900 actively exploited?

No active exploitation of CVE-2026-31900 has been confirmed so far. Continue monitoring, as exploit status can change.

Can CVE-2026-31900 be exploited remotely?

Yes. CVE-2026-31900 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-2026-31900?

CVE-2026-31900 has a CVSS score of 9.8 (CRITICAL).

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CRITICAL

CVE-2026-31900

CWE-20Published: March 11, 2026· Updated: Mar 16, 2026

9.8

CVSS v3.1

EPSS:0.12%probability of exploitation in 30 daysPercentile:30.2th

Official Description

Black is the uncompromising Python code formatter. Black provides a GitHub action for formatting code. This action supports an option, use_pyproject: true, for reading the version of Black to use from the repository pyproject.toml. A malicious pull request could edit pyproject.toml to use a direct URL reference to a malicious repository. This could lead to arbitrary code execution in the context of the GitHub Action. Attackers could then gain access to secrets or permissions available in the context of the action. Version 26.3.0 fixes this vulnerability.

NVD Source

Technical Analysis

CVE-2026-31900 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

A successful exploit results in complete confidentiality breach (data exposure), full integrity compromise (data manipulation), availability disruption (denial of service), with a CVSS base score of 9.8.