How severe is CVE-2021-32724?

CVE-2021-32724 has a CVSS score of 9.9/10, rated CRITICAL. Immediate patching is strongly recommended.

Which packages are affected by CVE-2021-32724?

CVE-2021-32724 affects the following packages: check-spelling/check-spelling (GitHub Actions). Ecosystems affected: GitHub Actions.

How do I fix CVE-2021-32724?

Update check-spelling/check-spelling to 0.0.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32724 is resolved across your whole dependency graph.

How do I detect CVE-2021-32724 in my GitHub Actions dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for check-spelling/check-spelling. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2021-32724 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2021-32724?

O3 pinpoints whether CVE-2021-32724 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2021-32724 actively exploited in the wild?

No public exploit code has been indexed for CVE-2021-32724 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2021-32724?

CVE-2021-32724 has an EPSS (Exploit Prediction Scoring System) score of 2.3%, placing it in the 81th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2021-32724?

CVE-2021-32724 is classified as CWE-532 (CWE-532). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2021-32724 published, and has it been updated?

CVE-2021-32724 was published on September 9, 2021 and was last updated on March 13, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 GitHub Actions

CVE-2021-32724

CRITICAL

check-spelling workflow vulnerable to token leakage via symlink attack

Also known asGHSA-g86g-chm8-7r2p

Published

Sep 9, 2021

Updated

Mar 13, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

2.3%probability of exploitation in next 30 days

Lower Risk81th percentile+1.94%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

📦check-spelling/check-spelling

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects GitHub Actions packages — download data is not available via public APIs for these ecosystems.

Description

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 Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦GitHub Actions	`check-spelling/check-spelling`	all versions	0.0.19

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for check-spelling/check-spelling. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update check-spelling/check-spelling to 0.0.19 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-32724 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2021-32724 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2021-32724. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

check-spelling is a github action which provides CI spell checking. In affected versions and for a repository with the [check-spelling action](https://github.com/marketplace/actions/check-spelling) 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

O3 Security · Impact-Aware SCA

Is CVE-2021-32724 in your dependencies?

O3 detects CVE-2021-32724 across GitHub Actions dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

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