CVE-2026-118762

Monkeytype: fork PR can execute code with elevated GITHUB_TOKEN

State
Published
Severity
9.3 Critical
Published
Oct 29, 2026
Updated
Oct 29, 2026
Reserved
Oct 28, 2026

Read the record on cve.org

Description

Monkeytype is a minimalistic and customizable typing test. Prior to 26.43.0, the .github/workflows/fix-formatting.yml workflow runs on pull_request_target with repository write permissions, checks out a fork pull request, installs dependencies from the fork's package.json, and invokes the fork-controlled oxfmt binary. Because actions/checkout persists the elevated GITHUB_TOKEN in Git configuration until after untrusted code executes, an external contributor whose pull request receives the format label can run arbitrary code, read or exfiltrate the token, and push repository content or modify pull requests and issues. The issue affects the repository CI workflow, not the Monkeytype application or user data. This issue is fixed in version 26.43.0.

Scores

CVSSScoreVectorSource
3.19.3 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:NGitHub_M

Weaknesses

  • CWE-829 Inclusion of Functionality from Untrusted Control Sphere

Affected Products

ProductVersions
monkeytypemonkeytypegame
  • < 26.43.0Affected

References

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