CVE-2026-55418 Details
Description
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.
A vulnerability in FastGPT's file handling for S3 object keys allows for unauthorized access to files from different teams. This issue exists in versions prior to 4.15.0-beta5. The vulnerability arises because the application does not properly verify that the S3 keys used to sign or read objects belong to the caller's team. As a result, an attacker can exploit this by using keys from other teams to access files through the chat-file presign or dataset preview endpoints. The chat-file presign endpoint can be accessed by anyone with a public share link, while the dataset preview endpoint is available to any authenticated user with write access to a dataset.
Update the file handlers to bind S3 object keys to the authorized team before signing or reading. This includes parsing the key to ensure it matches the authorized app and user, and verifying the ownership of dataset files before access is granted.
Metrics
CVSS 4.0 Severity and Vector Strings:
VolerionCVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
Volerion
Assessed Jul 7, 2026CISA-ADP
Assessed Jul 9, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://github.com/labring/FastGPT/commit/decb6d2fb1417fb9e2bca145d2dcc9cbcf06396c | [email protected] | Source CodeVendor |
| https://github.com/labring/FastGPT/pull/7104 | [email protected] | Source CodeVendor |
| https://github.com/labring/FastGPT/releases/tag/v4.15.0-beta5 | [email protected] | Release NotesVendor |
| https://github.com/labring/FastGPT/security/advisories/GHSA-6rxv-p43w-mmx5 | [email protected] | AdvisoryRemedyVendor |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-639 | Authorization Bypass Through User-Controlled Key | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| Labring FastGPT | < 4.15.0-beta5 (semver) |
CPE
Remediation
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Change History
2 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 9, 2026 | CVE Modified | CISA-ADP |
| Jul 7, 2026 | New CVE Received | [email protected] |