CVE-2026-55418
FastGPT: S3 presign/read handlers do not bind the object key to the caller's team (cross-team file disclosure)
CVSS Score
8.6
EPSS Score
0.3%
EPSS Percentile
22th
FastGPT is an open source AI knowledge base platform. Prior to v4.15.0-beta5, two FastGPT file handlers authorize an unrelated resource and then sign or read an S3 object using a key taken directly from the request, without checking that the key belongs to the caller's team. Because S3 object keys are global within the bucket and carry the tenant id only as a path segment, an attacker can supply another team's key and obtain its file contents through the chat-file presign endpoint or dataset preview endpoint. This issue is fixed in version v4.15.0-beta5.
| CWE | CWE-639 |
| Vendor | labring |
| Product | fastgpt |
| Published | Jul 7, 2026 |
| Last Updated | Jul 9, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
High
Integrity
None
Availability
None
Affected Versions
labring / FastGPT
< 4.15.0-beta5
References
github.com: https://github.com/labring/FastGPT/security/advisories/GHSA-6rxv-p43w-mmx5 github.com: https://github.com/labring/FastGPT/pull/7104 github.com: https://github.com/labring/FastGPT/commit/decb6d2fb1417fb9e2bca145d2dcc9cbcf06396c github.com: https://github.com/labring/FastGPT/releases/tag/v4.15.0-beta5