LangBot's plugin runtime (pip package langbot_plugin) through 0.4.17 starts a debug WebSocket server on 0.0.0.0:5401 (/plugin/ws) whose authentication is gated on plugin_debug_key, which defaults to an empty string and is never set by the upstream repository, Docker image, or docker-compose (which additionally publishes port 5401 to the host); the key check is therefore skipped entirely. Any remote attacker able to reach the port can register an arbitrary "debug plugin" without credentials. Because events are broadcast to all initialized plugins without filtering, the attacker's plugin receives the full context of every IM message event (including private chats, message chains, and user/sender IDs in plaintext) and can inject forged replies, send messages as any configured bot, enumerate bot UUIDs, invoke configured LLM models, read knowledge-base contents, and register malicious tools that feed every user's LLM pipeline. Registering with "prod_mode": true causes later legitimate installations of a plugin with the same author/name to be rejected, resulting in persistent denial of service. No patched version was available at the time of publication.
Advisories
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Fixes
Solution
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Workaround
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References
History
Mon, 14 Sep 2026 13:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | LangBot's plugin runtime (pip package langbot_plugin) through 0.4.17 starts a debug WebSocket server on 0.0.0.0:5401 (/plugin/ws) whose authentication is gated on plugin_debug_key, which defaults to an empty string and is never set by the upstream repository, Docker image, or docker-compose (which additionally publishes port 5401 to the host); the key check is therefore skipped entirely. Any remote attacker able to reach the port can register an arbitrary "debug plugin" without credentials. Because events are broadcast to all initialized plugins without filtering, the attacker's plugin receives the full context of every IM message event (including private chats, message chains, and user/sender IDs in plaintext) and can inject forged replies, send messages as any configured bot, enumerate bot UUIDs, invoke configured LLM models, read knowledge-base contents, and register malicious tools that feed every user's LLM pipeline. Registering with "prod_mode": true causes later legitimate installations of a plugin with the same author/name to be rejected, resulting in persistent denial of service. No patched version was available at the time of publication. | |
| Title | LangBot through 0.4.17 Unauthenticated Plugin Registration via WebSocket | |
| First Time appeared |
Langbot
Langbot langbot |
|
| Weaknesses | CWE-306 | |
| CPEs | cpe:2.3:a:langbot:langbot:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Langbot
Langbot langbot |
|
| References |
| |
| Metrics |
cvssV3_1
|
Projects
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Status: PUBLISHED
Assigner: VulnCheck
Published:
Updated: 2026-09-14T13:29:58.833Z
Reserved: 2026-09-14T11:34:24.687Z
Link: CVE-2026-90938
No data.
Status : Received
Published: 2026-09-14T13:19:32.430
Modified: 2026-09-14T14:17:20.117
Link: CVE-2026-90938
No data.
OpenCVE Enrichment
No data.
Weaknesses