REBUILD through 4.5.0 Authorization Bypass via aibot2 Chat Endpoints chatid

Advisories

REBUILD through 4.5.0 Authorization Bypass via aibot2 Chat Endpoints chatid

Severity: medium
Date: 10/14/2026
Affecting: rebuild <= 4.5.0
CVE: CVE-2026-110611
CWE: CWE-639 Authorization Bypass Through User-Controlled Key
CVSS: 6.0
CVSS V4 Vector: CVSS:4.0/AV:N/AC:H/AT:N/PR:L/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
References: https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/getrebuild-rebuild-aibot-chat-idor
https://github.com/getrebuild/rebuild/blob/48c6cc42f9c331cc57c057fa9c66d6cbda990131/src/main/java/com/rebuild/web/aibot/AiBot2Controller.java#L151-L203
https://github.com/getrebuild/rebuild/blob/48c6cc42f9c331cc57c057fa9c66d6cbda990131/src/main/java/com/rebuild/core/aibot2/ChatManager.java#L99-L101
Credit: hieuPenguinnn
Description: REBUILD through 4.5.0 contains an authorization bypass vulnerability in AiBot2Controller /aibot2 endpoints that act on a caller-supplied chatid without verifying ownership. Authenticated low-privilege users can supply another user's chatid to chat-init, chat-delete, chat-feedback, or chat-stream-stop to read, delete, exfiltrate, or interrupt AI assistant conversations.

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