GHSA-52vm-mxx8-f227
Phantom: Arbitrary file write and decode-bomb DoS via unconfined MCP tool paths
GHSA-52vm-mxx8-f227 is a high vulnerability (CVSS 7.7) in phantom-audio, published July 9, 2026. No source lists public exploit code. Fixed in phantom-audio 1.3.1.
- Severity
- 7.7 HighCVSS 3.1, GitHub Advisories
- Exploit chance
- UnscoredNo EPSS score yet
- Exploitation
- None knownNot on CISA’s or ENISA’s lists
- Fixed in
1.3.1phantom-audio +1 more
Description
Impact
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.
Patches
Fixed in 1.3.1:
- File writes are always confined to
PHANTOM_OUTPUT_DIR(default~/.phantom/output); symlinks resolved and re-verified on the final path. - Decode/duration/size guards mirrored onto the separation and render paths (plus ffmpeg
-max_alloc/-t/-fs). - Atomic
O_CREAT|O_EXCLoutput creation in reference matching and symlink-TOCTOU hardening on confined input reads.
Workarounds
Set PHANTOM_OUTPUT_DIR (and optionally PHANTOM_AUDIO_DIR) to dedicated directories before starting the server.
Credit
Found during an internal security audit.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Affected packages
| Package | Affected | Fixed |
|---|---|---|
phantom-audioPyPI | through 1.3.0 | 1.3.1 |
phantom-audioPyPI | before 1.3.1, plus listed versions 1.1.01.2.01.2.11.2.21.2.31.2.41.3.0 | 1.3.1 |
What each source reports
GitHub Advisories Score used
Phantom: Arbitrary file write and decode-bomb DoS via unconfined MCP tool paths
Impact
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.
Patches
Fixed in 1.3.1:
- File writes are always confined to
PHANTOM_OUTPUT_DIR(default~/.phantom/output); symlinks resolved and re-verified on the final path. - Decode/duration/size guards mirrored onto the separation and render paths (plus ffmpeg
-max_alloc/-t/-fs). - Atomic
O_CREAT|O_EXCLoutput creation in reference matching and symlink-TOCTOU hardening on confined input reads.
Workarounds
Set PHANTOM_OUTPUT_DIR (and optionally PHANTOM_AUDIO_DIR) to dedicated directories before starting the server.
Credit
Found during an internal security audit.
- Record
GHSA-52vm-mxx8-f227- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-22, CWE-73, CWE-400
- Updated
- 2026-11-02
OSV
Phantom: Arbitrary file write and decode-bomb DoS via unconfined MCP tool paths
Impact
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.
Patches
Fixed in 1.3.1:
- File writes are always confined to
PHANTOM_OUTPUT_DIR(default~/.phantom/output); symlinks resolved and re-verified on the final path. - Decode/duration/size guards mirrored onto the separation and render paths (plus ffmpeg
-max_alloc/-t/-fs). - Atomic
O_CREAT|O_EXCLoutput creation in reference matching and symlink-TOCTOU hardening on confined input reads.
Workarounds
Set PHANTOM_OUTPUT_DIR (and optionally PHANTOM_AUDIO_DIR) to dedicated directories before starting the server.
Credit
Found during an internal security audit.
- Record
GHSA-52vm-mxx8-f227- CVSS 3.1
- 7.7 High
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-22, CWE-400, CWE-73
- Updated
- 2026-11-02
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | GitHub Advisories, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.