CVE-2026-55418FastGPT: S3 presign/read handlers do not bind the object key to the caller's team (cross-team file disclosure)
- 8.6HighCVSS base score
- 0.48%Exploitation in 30 daysEPSS · top 58% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By GitHub_M
- 21 days later
· 21 days later
Published
- 2 days later
· 2 days later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | High8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N |
| NVDNVD · Deferred | 3.1 | High8.6 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 0.48% · top 58% of all CVEs (15 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.6.
Affected products
References
References4
- https://github.com/labring/FastGPT/security/advisories/GHSA-6rxv-p43w-mmx5 (opens in a new tab)x_refsource_CONFIRM
- https://github.com/labring/FastGPT/pull/7104 (opens in a new tab)x_refsource_MISC
- https://github.com/labring/FastGPT/commit/decb6d2fb1417fb9e2bca145d2dcc9cbcf06396c (opens in a new tab)x_refsource_MISC
- https://github.com/labring/FastGPT/releases/tag/v4.15.0-beta5 (opens in a new tab)x_refsource_MISC
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-42115 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-55418)Record last updated .