Executive brief
Cocotais Bot is a chatbot framework used to automate messaging in group chats. The bot's built-in /echo command fails to filter platform-specific control tags, allowing unprivileged users to inject tags that trigger privileged actions like @everyone mentions, bypassing normal permission controls and disrupting chat operations.
Technical details
The vulnerability is an improper neutralization of special elements (CWE-74) in the /echo command handler. When a user sends /echo <qqbot-at-everyone />, the bot echoes the payload verbatim without sanitization. The platform then interprets the injected <qqbot-at-everyone /> tag as a legitimate bot-issued @全体成员 (at-everyone) mention, even though the original user lacks permission for this action. The attack is network-reachable and requires no authentication or user interaction beyond sending a malicious message. An attacker can repeatedly trigger spam notifications and disrupt the chat. The vulnerability is fixed in version 1.6.2 and later.
Affected products
- Cocotais Cocotais Bot >1.5.0-test2-hotfix, <=1.6.1
Timeline
- 2025-05-17: disclosed
- 2025-05-19: advisory
- 2025-05-19: patched: Version 1.6.2 fixes the vulnerability