Check Spelling
CVE-2021-32724
CRITICAL
Severity by source
AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Primary rating from Vendor (github) · only source for this CVE.
CVSS VectorVendor: github
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Lifecycle Timeline
1DescriptionCVE.org
check-spelling is a github action which provides CI spell checking. In affected versions and for a repository with the check-spelling action enabled that triggers on pull_request_target (or schedule), an attacker can send a crafted Pull Request that causes a GITHUB_TOKEN to be exposed. With the GITHUB_TOKEN, it's possible to push commits to the repository bypassing standard approval processes. Commits to the repository could then steal any/all secrets available to the repository. As a workaround users may can either: Disable the workflow until you've fixed all branches or Set repository to Allow specific actions. check-spelling isn't a verified creator and it certainly won't be anytime soon. You could then explicitly add other actions that your repository uses. Set repository Workflow permissions to Read repository contents permission. Workflows using check-spelling/check-spelling@main will get the fix automatically. Workflows using a pinned sha or tagged version will need to change the affected workflows for all repository branches to the latest version. Users can verify who and which Pull Requests have been running the action by looking up the spelling.yml action in the Actions tab of their repositories, e.g., https://github.com/check-spelling/check-spelling/actions/workflows/spelling.yml - you can filter PRs by adding ?query=event%3Apull_request_target, e.g., https://github.com/check-spelling/check-spelling/actions/workflows/spelling.yml?query=event%3Apull_request_target.
AnalysisAI
check-spelling is a github action which provides CI spell checking. Rated critical severity (CVSS 9.9), this vulnerability is remotely exploitable, low attack complexity.
Technical ContextAI
This vulnerability is classified under CWE-532. check-spelling is a github action which provides CI spell checking. In affected versions and for a repository with the check-spelling action enabled that triggers on pull_request_target (or schedule), an attacker can send a crafted Pull Request that causes a GITHUB_TOKEN to be exposed. With the GITHUB_TOKEN, it's possible to push commits to the repository bypassing standard approval processes. Commits to the repository could then steal any/all secrets available to the repository. As a workaround users may can either: Disable the workflow until you've fixed all branches or Set repository to Allow specific actions. check-spelling isn't a verified creator and it certainly won't be anytime soon. You could then explicitly add other actions that your repository uses. Set repository Workflow permissions to Read repository contents permission. Workflows using check-spelling/check-spelling@main will get the fix automatically. Workflows using a pinned sha or tagged version will need to change the affected workflows for all repository branches to the latest version. Users can verify who and which Pull Requests have been running the action by looking up the spelling.yml action in the Actions tab of their repositories, e.g., https://github.com/check-spelling/check-spelling/actions/workflows/spelling.yml - you can filter PRs by adding ?query=event%3Apull_request_target, e.g., https://github.com/check-spelling/check-spelling/actions/workflows/spelling.yml?query=event%3Apull_request_target. Affected products include: Check-Spelling.
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.
Same technique Authentication Bypass
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External POC / Exploit Code
Leaving vuln.today