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CVE-2026-114134

Black: GitHub Action installs unvalidated required-version from pyproject.toml

CVSS score

—

EPSS probability

—

Risk score

—

Published

5 h ago

OverviewPublic Exploits (0)NewsroomVulnerability Timeline
Patch status has not yet been verified

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Vulnerability description

DayBreach AI Explanation

Verified against sources

Black GitHub Action Unvalidated Version Installation Vulnerability

Sources read

1

Source agreement

Tam uyum

Evidence confidence

%55

Short explanation

CVE-2026-114134 is a remote code execution vulnerability in the Black GitHub Action component due to unvalidated reading of the tool.black.required-version value.

Why does it matter?

Attackers can execute remote code in a victim's repository by submitting a pull request containing a malicious pyproject.toml file.

What should be done?

  • Follow the vendor advisory and updates
  • Review the Black GitHub Action configurations in use
Chain of evidence and sources2 verified claims

CVE-2026-114134 açığı, Black GitHub Action bileşeninin tool.black.required-version değerini doğrulamadan kabul etmesiyle ortaya çıkar.

S0 · daybreach-canonicalS1 · github

Açık, use_pyproject ayarı True olduğunda uzaktan kod yürütülmesine olanak tanır.

S0 · daybreach-canonicalS1 · github
Show the technical text from the sources

### Summary The GitHub Action bundled with Black can read the version from `tool.black.required-version` if `use_pyproject` is set to True. This version is not validated and therefore can be used to execute untrusted code in the context of a victim's repository. ### Details This is similar to the previous CVE-2026-31900. The value in `tool.black.required-version` is accepted as the version to be installed by the action without validation. ### Proof of concept Reproduction requires a victim to use Black's GitHub Action with `use_pyproject: true`. The attacker would then issue a PR to the victim's repository with `pyproject.toml` edited so that Black points to a malicious repository. ### Impact This is a remote code execution vulnerability impacting users using the GitHub Action bundled with psf/black and using the `use_pyproject: true` setting.

CWE: CWE-829

This explanation was compiled automatically from the source records. Scores, active exploitation, patch and exploit status come straight from the sources.

IMPACT: Affected Products and Software

Affected Products

The following products are affected by CVE-2026-114134 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.

IDVENDORPRODUCTACTION
1pypiblack View
Total affected vendors: 1|Products: 1

RED HAT CSAF/VEX: Product Impact Check

Red Hat has not yet published a CSAF/VEX impact record for this CVE. This does not mean “not affected”.

SCORING: CVSS from Multiple Sources

CVSS Scores

The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.

SCOREVERSIONSEVERITYVECTORSOURCE
8.7CVSS 4.0—Vector not publishedGitHub Advisory

Patch and Remediation Guide

Solution & Remediation Advisory

Patch status unknown

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

Confirm the affected product and version against the source evidence above.
Restrict access to internet-facing services and apply network segmentation.
Until a patch is confirmed, follow the vendor advisory; do not read an unknown status as “no patch”.
Monitor server logs and network endpoints for signs of anomalous execution.

Public exploit and active exploitation status

Verified exploit intelligence

No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.

Weakness Classification and Attack Patterns (CWE & CAPEC)

CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-114134 is associated with the following CWEs:

CWE-829: Common Weakness Enumeration Entry CWE-829

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-114134 weaknesses.

CAPEC-66: SQL InjectionCAPEC-126: Path TraversalCAPEC-28: OS Command Injection

Official Sources and Advisories

https://github.com/psf/black/security/advisories/GHSA-cg8m-r9f2-5wm2vendor-advisoryhttps://github.com/psf/black/pull/5510vendor-advisoryhttps://github.com/psf/black/commit/ac1f71563aeccf73cf13ece00f231d9d6c66a514vendor-advisoryhttps://github.com/psf/black/releases/tag/26.10.1vendor-advisoryhttps://github.com/advisories/GHSA-cg8m-r9f2-5wm2vendor-advisory

Yama durumu bilinmiyor

İncelenen resmî kaynaklarda yama durumu doğrulanamadı. Bu sonuç “yama yok” anlamına gelmez.

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Weakness Type (CWE & CAPEC)

CWE-829

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CVE-2026-114134 · Black: GitHub Action installs unvalidated…