dbcve.org
PostizApplication · Gitroom

CVE-2026-42298

CRITICAL · 9.8 CVSS v3.1 Published 2026-05-08
Fix available
A fix is available. Upgrade to 2.21.7 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Postiz is an AI social media scheduling tool. Prior to commit da44801, a "Pwn Request" vulnerability in the Build and Publish PR Docker Image workflow (.github/workflows/pr-docker-build.yml) allows any unauthenticated user to execute arbitrary code during the Docker build process and exfiltrate a highly privileged GITHUB_TOKEN (write-all permissions). This can be achieved simply by opening a Pull Request from a fork with a maliciously modified Dockerfile.dev. This issue has been patched via commit da44801.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A 'Pwn Request' vulnerability in the GitHub Actions workflow (.github/workflows/pr-docker-build.yml) allows unauthenticated attackers to execute arbitrary code during Docker builds by submitting a maliciously modified Dockerfile.dev via a pull request from a fork, enabling exfiltration of the highly privileged GITHUB_TOKEN with write-all permissions.

MitigationUpgrade to the patched version (commit da44801 or later) and audit all GitHub Actions workflows to ensure they do not blindly trust artifacts from untrusted sources such as pull requests from forks.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
PostizApplication
Affected:< 2.21.7

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify if Gitroom Postiz is in use
    Check your project's package.json, composer.json, or dependency files for the 'postiz' package, or check running containers/services for the Postiz application
    Affected if The application uses Gitroom Postiz and the version is below 2.21.7
  2. Locate the vulnerable workflow file
    Navigate to .github/workflows/pr-docker-build.yml in your repository
    Affected if This workflow file exists and contains Docker build configurations that process Dockerfile.dev from pull requests
  3. Check if the workflow runs on pull request events
    Review the 'on' triggers in .github/workflows/pr-docker-build.yml and verify if 'pull_request' events are enabled without path restrictions
    Affected if The workflow triggers on pull_request events from external forks
  4. Verify the workflow uses a privileged GITHUB_TOKEN
    Inspect the workflow YAML for 'GITHUB_TOKEN' usage, particularly if permissions include write-access to repository contents
    Affected if The workflow uses a GITHUB_TOKEN with broad write permissions and runs on external PRs
  5. Confirm Dockerfile.dev is built from PR context
    Check if the workflow builds or processes a 'Dockerfile.dev' file that originates from the pull request source branch without validation
    Affected if The workflow builds Dockerfile.dev directly from incoming pull requests without sanitizing the build context

You are affected if you run Gitroom Postiz version below 2.21.7 and have the .github/workflows/pr-docker-build.yml workflow that builds untrusted Dockerfile.dev from fork-based pull requests using a privileged GITHUB_TOKEN.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.21.7 or later
Fixed in 2.21.7
Vendor patch github.com →
Interim mitigation

Upgrade to the patched version (commit da44801 or later) and audit all GitHub Actions workflows to ensure they do not blindly trust artifacts from untrusted sources such as pull requests from forks.

Recommended fix High confidence

Postiz >= 2.21.7

  1. Upgrade Postiz to version 2.21.7 or later to receive the patched workflow file
  2. Verify the .github/workflows/pr-docker-build.yml file contains the fix from commit da44801 (which should be included in the upgrade)
  3. If running a self-hosted instance, ensure you pull the latest Docker image after upgrading

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Postiz Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,770
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-42298 in production — separate from our analysis above.

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data