CVE-2021-32724

CRITICAL

check-spelling < 0.0.19 - Sensitive Information Exposure via GitHub Token Leak

Title source: llm
STIX 2.1

Exploitation Summary

EIP tracks 1 public exploit for CVE-2021-32724. PoCs published by MaximeSchlegel.

AI-analyzed exploit summary This repository is a placeholder for demonstrating CVE-2021-32724, a vulnerability in the Check Spelling Workflow. It contains no functional exploit code, only configuration files for a spelling check workflow and a minimal README indicating it is a target for the exploit.

Description

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 workflow](https://docs.github.com/en/actions/managing-workflow-runs/disabling-and-enabling-a-workflow) until you've fixed all branches or Set repository to [Allow specific actions](https://docs.github.com/en/github/administering-a-repository/managing-repository-settings/disabling-or-limiting-github-actions-for-a-repository#allowing-specific-actions-to-run). 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](https://docs.github.com/en/github/administering-a-repository/managing-repository-settings/disabling-or-limiting-github-actions-for-a-repository#setting-the-permissions-of-the-github_token-for-your-repository) 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.

Exploits (1)

nomisec STUB
by MaximeSchlegel · poc
https://github.com/MaximeSchlegel/CVE-2021-32724-Target

This repository is a placeholder for demonstrating CVE-2021-32724, a vulnerability in the Check Spelling Workflow. It contains no functional exploit code, only configuration files for a spelling check workflow and a minimal README indicating it is a target for the exploit.

Classification
Stub 90%
Attack Type
Other
Complexity
Trivial
Reliability
Theoretical
Target: Check Spelling Workflow
No auth needed
Prerequisites: A vulnerable version of the Check Spelling Workflow
devstral-2 · analyzed Feb 18, 2026 Full analysis →

Scores

CVSS v3 9.9
EPSS 0.0032
EPSS Percentile 56.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Details

CWE
CWE-532
Status published
Products (2)
check-spelling/check-spelling < 0.0.19
GitHub Actions/check-spelling/check-spelling 0 - 0.0.19GitHub Actions
Published Sep 09, 2021
Tracked Since Feb 18, 2026