A detailed exploit writeup for CVE-2026-5674, a sandbox escape vulnerability in PipeWire's PulseAudio compatibility layer. The bug chain involves three issues: authentication cookies are read but never validated (any 256 bytes pass), module loading is enabled by default, and dlopen() accepts arbitrary paths with no validation. A Flatpak app with only --socket=pulseaudio and write access to /tmp can load a malicious .so into PipeWire (which runs outside the sandbox), achieving full user-context code execution. The vulnerability was discovered using Claude Code and Opus 4.6, confirmed on Fedora, Ubuntu 24.04, and Debian 13, and affects any sandbox tech that mounts the PulseAudio socket — including Docker. CVSS score is 8.8 (High). The fix restricts dlopen() to allowlisted LADSPA plugin directories. Red Hat has released a patch.
