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.
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History

Thu, 29 Oct 2026 17:00:00 +0000

Type Values Removed Values Added
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.
Title Monkeytype: fork PR can execute code with elevated GITHUB_TOKEN
Weaknesses CWE-829
References
Metrics cvssV3_1

{'score': 9.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-29T16:50:44.341Z

Reserved: 2026-10-28T19:20:05.017Z

Link: CVE-2026-118762

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Deferred

Published: 2026-10-29T17:18:07.070

Modified: 2026-10-29T17:18:07.200

Link: CVE-2026-118762

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-10-29T18:30:14Z

Weaknesses