Executive brief
LobeHub is an AI chat application platform that allows users to upload files to a knowledge base. An authenticated attacker can intercept and modify upload requests to bypass storage quotas, upload arbitrary files to unintended locations, and misrepresent file sizes to the billing system. This allows circumventing subscription limits, exhausting server resources, and causing service degradation for all users on a shared plan.
Technical details
The file upload feature in LobeHub's Knowledge Base does not validate the integrity of presigned upload requests, allowing modification of user-controlled parameters such as file name and size. An authenticated attacker can intercept POST requests to /trpc/lambda/file.createFile, modify the name and size fields, and upload files beyond the subscription plan's storage limits while misrepresenting actual file sizes to the server's quota tracking system. The root cause is improper authorization and validation of request parameters (CWE-73: External Control of File Name or Path). The attack requires authentication and network access but no additional user interaction. Successful exploitation results in quota bypass, storage exhaustion, billing fraud, service degradation, and potential denial of service affecting other users. The vulnerability is fixed in version 1.143.3.
Affected products
- LobeHub LobeHub all versions up to 1.143.2
Timeline
- 2026-01-30: disclosed: Published on NVD
- 2026-02-01: disclosed: Published on GitHub Security Advisory
- 2026-02-01: patched: Fix released in version 1.143.3