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CVE-2026-90938— LangBot through 0.4.17 Unauthenticated Plugin Registration via WebSocket

Quick assessment

Affected
langbot-app LangBot
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

LangBot 的插件运行时（pip 包 langbot_plugin）在 0.4.17 及更早版本中，会在 0.0.0.0:5401 端口（路径 /plugin/ws）启动一个调试 WebSocket 服务器。该服务器的认证依赖于 ，而此键默认值为空字符串，且在上游仓库、Docker 镜像及 docker-compose（后者还会将 5401 端口发布到宿主机）中均未被设置，因此认证检查实际上被完全跳过。任何能够访问该端口的远程攻击者都可以无需凭据注册一个任意的“调试插件”。由于事件会不加过滤地广播给所有已初始化

CVSS 8.6 · High
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I. Basic Information for CVE-2026-90938

Vulnerability Information
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Vulnerability Title
LangBot through 0.4.17 Unauthenticated Plugin Registration via WebSocket
Source: CVE Program / CVE List V5
Vulnerability 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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:L
Source: CVE Program / CVE List V5
Vulnerability Type
关键功能的认证机制缺失
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
langbot-app LangBot 0 ~ 0.4.17 -

II. Public POCs for CVE-2026-90938

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III. Intelligence Information for CVE-2026-90938

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Vendor Advisories for CVE-2026-90938 (2)

IV. Related Vulnerabilities

Same product: LangBot
Same vendor: langbot-app
Same weakness: CWE-306

V. Comments for CVE-2026-90938

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