CVE-2026-68929
Deferred Deferred - Pending Action

Authentication Bypass in FastGPT via WeChat ShareID

Vulnerability report for CVE-2026-68929, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-28

Last updated on: 2026-09-09

Assigner: GitHub, Inc.

Description

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.

CVSS Scores

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Meta Information

Published
2026-08-28
Last Modified
2026-09-09
Generated
2026-09-17
AI Q&A
2026-08-28
EPSS Evaluated
2026-09-15
NVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
labring fastgpt to 4.15.2 (exc)

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-862 The product does not perform an authorization check when an actor attempts to access a resource or perform an action.
CWE-306 The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

Attack-Flow Graph

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Executive Summary

CVE-2026-68929 is a high-severity vulnerability in FastGPT's WeChat integration. It allows unauthenticated attackers to hijack WeChat bot channels or take them offline by exploiting missing authorization checks on specific endpoints. Attackers only need a victim's public shareId, which is exposed in shared URLs or embeds, to perform these actions.

Detection Guidance

Check FastGPT logs for suspicious activity on the affected endpoints: POST /api/support/outLink/wechat/logout, POST /api/support/outLink/wechat/qrcode/generate, and POST /api/support/outLink/wechat/qrcode/status. Monitor for repeated requests with unusual shareId values or failed authentication attempts.

Impact Analysis

This vulnerability can disrupt your FastGPT service by taking WeChat bots offline (DoS). Attackers can also hijack your WeChat channel to intercept private responses, consume your AI points, and replace legitimate bot bindings with their own. All an attacker needs is your public shareId.

Compliance Impact

This vulnerability could lead to unauthorized access to private AI responses and WeChat bot interactions, potentially exposing sensitive user data. This may violate GDPR's data protection principles (Article 5) and HIPAA's requirements for safeguarding protected health information, depending on the data processed by FastGPT.

Mitigation Strategies

Upgrade FastGPT to version 4.15.2 or later to apply the security fixes. Ensure all WeChat-related API endpoints are restricted to authenticated users with proper team ownership validation. Review and revoke any unauthorized WeChat bot bindings.

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