PyPI · phantom-audio
Phantom: Arbitrary file write and decode-bomb DoS via unconfined MCP tool paths
In Phantom <= 1.3.0, when PHANTOM_OUTPUT_DIR was unset (the default), the MCP tools accepted arbitrary absolute output paths with no confinement. Anything able to send tool calls (e.g. an AI agent driving the MCP interface) could write or overwrite arbitrary files the process user can write — including shell startup files (~/.zshrc) or a Reaper __startup.lua, which is effectively local code execution on a developer workstation.
Separately, the stem-separation and render paths decoded input audio with no size/duration cap (the analysis path was already guarded). A small, highly compressed FLAC/OGG could expand to multi-gigabyte PCM, causing memory-exhaustion DoS, and widened exposure to decoder bugs including libsndfile CVE-2026-37555.
Fixed in 1.3.1:
PHANTOM_OUTPUT_DIR (default ~/.phantom/output); symlinks resolved and re-verified on the final path.-max_alloc/-t/-fs).O_CREAT|O_EXCL output creation in reference matching and symlink-TOCTOU hardening on confined input reads.Set PHANTOM_OUTPUT_DIR (and optionally PHANTOM_AUDIO_DIR) to dedicated directories before starting the server.
Found during an internal security audit.
Is your project exposed to this? Stateward checks every dependency on every pull request and flags it only if your code actually reaches it.
Check my repoSources: CISA KEV (public domain), OSV.dev & GitHub Advisory Database (CC-BY-4.0), FIRST EPSS, NVD/CWE (public domain). Served live from the Stateward advisory database.