ComfyUI-Manager has an Unprotected Alternate Channel (CWE-420)

Impact

An Unprotected Alternate Channel (CWE-420) vulnerability was discovered in ComfyUI-Manager versions prior to 3.38.

Vulnerability Details

In affected versions, ComfyUI-Manager stored its configuration in the user/default/ComfyUI-Manager/ directory, which was accessible via ComfyUI's web APIs without proper access control. This unprotected alternate channel allowed remote attackers to read and manipulate configuration files and critical data through the web interface.

Potential Attack Scenarios

An attacker exploiting this vulnerability could:

• Modify security settings: Lower the security level from "strong" to "weak" to enable more dangerous operations
• Tamper with custom node sources: Add malicious custom node repositories
• Manipulate snapshot data: Corrupt or alter system snapshots
• Change manager behavior: Alter various manager configuration settings

Affected Configurations

| Configuration | Risk Level | |---------------|------------| | Systems running with --listen 0.0.0.0 (externally exposed) | HIGH | | Systems behind reverse proxy without proper access control | MEDIUM | | Local-only installations (default, localhost only) | NOT AFFECTED |

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Patches

This issue has been patched in ComfyUI-Manager version 3.38.

Requirements

| Component | Minimum Version | Notes | |-----------|-----------------|-------| | ComfyUI | v0.3.76+ | Required for System User Protection API | | ComfyUI-Manager | v3.38+ | Contains the security fix |

What the Patch Does

1. Path Migration: Configuration files moved from unprotected user/default/ComfyUI-Manager/ to protected user/__manager/
2. Protected Directory: The new __manager/ directory leverages ComfyUI's System User Protection API, which blocks external web API access
3. Security Level Enforcement: Settings below "normal" are automatically raised to "normal" during migration
4. Legacy Backup: Old data is backed up to .legacy-manager-backup/ with startup reminders until manually deleted
5. Fallback Protection: If ComfyUI < v0.3.76, Manager forces "strong" security mode, blocking new installations until ComfyUI is updated

Patch Details

• Commit: aaed1dc
• Pull Request: ComfyUI-Manager/#2338 ComfyUI/#10966
• Changes: +780 lines, −61 lines across 13 files

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Workarounds

If immediate upgrade is not possible, apply the following mitigations:

| Mitigation | Effectiveness | Effort | |------------|---------------|--------| | Remove --listen 0.0.0.0 flag (use localhost only) | HIGH | Low | | Implement firewall rules to block external access to ComfyUI ports | HIGH | Medium | | Use reverse proxy with authentication (e.g., nginx + basic auth) | HIGH | Medium | | Restrict network access to trusted IPs only | MEDIUM | Low |

Note: These are temporary mitigations. Upgrading to v3.38+ is strongly recommended.

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Resources

• NVD - CVE-2025-67303
• ComfyUI-Manager v3.38 Security Migration Guide
• Patch Pull Request ComfyUI-Manager/#2338
• Patch Pull Request ComfyUI/#10966

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Credit

This vulnerability was reported by Ricter Zheng (ricterzheng / 郑杜涛) from Tencent Xuanwu Lab [email protected]