Vulnerability · Published Oct 14, 2026 · Assigned by VulnCheck

CVE-2026-110611REBUILD through 4.5.0 Authorization Bypass via aibot2 Chat Endpoints chatid

Medium 5.9

In plain English

A medium-severity authorization bypass via user-controlled key in rebuild from getrebuild. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 32% of all known vulnerabilities).

Severity (CVSS 3.1)5.9Medium

Exploit odds (30 days)0.4%top 67.9% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official 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.

Affected products (as reported)

Vendor	Product	Versions
getrebuild	rebuild	0 – through 4.5.0

Weakness: CWE-639 · Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N

References

https://hackmd.io/@1ExmmukzRMWN7B4gQ4W-4Q/getrebuild-rebuild-aibot-chat-idor third-party-advisory
https://github.com/getrebuild/rebuild/blob/48c6cc42f9c331cc57c057fa9c66d6cbda990131/src/main/java/com/rebuild/web/aibot/AiBot2Controller.java#L151-L203 technical-description
https://github.com/getrebuild/rebuild/blob/48c6cc42f9c331cc57c057fa9c66d6cbda990131/src/main/java/com/rebuild/core/aibot2/ChatManager.java#L99-L101 technical-description
VulnCheck Advisory: REBUILD through 4.5.0 Authorization Bypass via aibot2 Chat Endpoints chatid third-party-advisory