🎯 New Report #3799010: TaskProcessing callback authorization bypass allows ex-members to post as Assistant Talk Bot
🔺Severity: Medium
👽 Reporter: kuninogu
⭐️ Reputation: 104
🛠 State: resolved
💼 Team: Nextcloud
💵 Bounty: null
🕐 Submitted: 2026-06-12
⏰ Disclosed: 2026-08-14 14:50:38
📝 Summary: A vulnerability was discovered that allowed an authenticated low-privilege user to cause the trusted Assistant Talk Bot to post attacker-guided AI-generated content into a Talk conversation, even after the user had left the conversation. The issue was caused by the Talk Bot's endpoint trusting the caller-supplied conversation token without verifying that the callback belonged to a task originally scheduled by the bot.
📂 Report JSON File: 3799010
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