CVE-2026-55418
HighCVSS 8.6Exploitation Probability (EPSS)
Low risk22th percentile - higher than 22% of all known CVEs
Summary
In FastGPT prior to v4.15.0-beta5, two 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.
Risk Assessment
The organization is at risk of leaking confidential data stored in S3, as an attacker can read files belonging to other teams without proper authorization.
Recommendation
Immediately upgrade FastGPT to version v4.15.0-beta5 or later, which includes a fix for this vulnerability.
Original NVD description (English source)
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.