CVE-2026-42298: Postiz: Arbitrary Code Execution and Token Exfiltration in pr-docker-build.yml via untrusted Dockerfile.dev

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.