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Fencer Intel
critical 9.3

CVE-2026-68929 json

FastGPT: Unauthenticated WeChat channel hijack and denial of service via shareId-only authorization

published 2mo ago modified 2mo ago also EUVD-2026-67310 , GHSA-q4pr-3qpg-9q5v

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository labring/FastGPT. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
9.3
version 4.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 38%
public exploits
0
none known

Summary

FastGPT is an open-source LLM platform for building AI applications on a knowledge base. In versions prior to 4.15.2, the WeChat (iLink) share-channel endpoints authorize requests using only the public shareId, with no authenticated identity or team-ownership check. As a result, an unauthenticated attacker who knows a victim team's shareId can take that team's WeChat bot offline or hijack the channel to their own bot: the logout endpoint is gated only by an existence check yet wipes the outLink's stored WeChat token, and the QR-code status endpoint performs no authorization at all and writes attacker-supplied bot credentials into the outLink identified by shareId. By generating a QR for a victim shareId, scanning it with their own WeChat, and calling the status endpoint, an attacker binds the victim team's app to the attacker's bot, exposing the app's private responses, displacing the legitimate binding, and consuming the victim's resources. The shareId is exposed in every shared chat URL, iframe, and embed, so it is not a secret. This issue is fixed in version 4.15.2.

Patch / fix

  • fastgpt fastgpt 4.14.29, 4.15.2

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
total
Assessed
2mo ago

Exploit prediction

0.44% chance of exploitation in the next 30 days, higher than 38% of all scored CVEs (FIRST EPSS, 2026-11-11).

Exploits and checks

  • github.com https://github.com/labring/FastGPT/security/advisories/GHSA-q4pr-3qpg-9q5v referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CNA 4.0 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Affected products

  • labring FastGPT

Classification

Weakness
  • CWE-862 Missing Authorization
  • CWE-306 Missing Authentication for Critical Functionality

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

The maintainers of labring/FastGPT published their own advisory on GitHub. Reviewed sources take precedence over it.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.