Vulnerability · Published Oct 16, 2026 · Assigned by VulnCheck
CVE-2026-11170799AI through 4.3.0 IDOR via /api/chatLog/querySingleChat Chat Message Disclosure
Medium 5.3
In plain English
A medium-severity authorization bypass via user-controlled key in 99AI from vastxie. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 24% of all known vulnerabilities).
Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.3%top 76.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known
Official description
99AI through 4.3.0 contains an insecure direct object reference vulnerability that allows unauthenticated attackers to read other users' chat messages because querySingleChat lacks an owner check. Attackers can send a fingerprint header to obtain a visitor JWT and iterate sequential chatId values to retrieve other users' message content and task data.
Affected products (as reported)
Weakness: CWE-639 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
References
- https://hackmd.io/@hieuPenguinnn/99ai-chatlog-unauth-export-and-idor third-party-advisory
- https://github.com/vastxie/99AI/blob/v4.3.0/service/src/modules/chatLog/chatLog.service.ts#L463-L475 technical-description
- https://github.com/vastxie/99AI/blob/v4.3.0/service/src/common/auth/jwtAuth.guard.ts technical-description
- https://github.com/vastxie/99AI product
- VulnCheck Advisory: 99AI through 4.3.0 IDOR via /api/chatLog/querySingleChat Chat Message Disclosure third-party-advisory