CVE-2026-85621
Received Received - Intake

LobeChat Webhook Signature Bypass in QQ and Feishu Adapters

Publication date: 2026-09-04

Last updated on: 2026-09-04

Assigner: VulnCheck

Description
LobeChat (LobeHub) 2.2.1 does not properly verify inbound chat-platform webhook signatures in the QQ and Feishu adapters. The webhook route (/api/agent/webhooks/:platform) is unauthenticated by design and delegates verification to each adapter; the QQ adapter performs no Ed25519 signature verification on dispatched message events, and the Feishu adapter only performs an optional static-token comparison that is skipped when no token is configured (the default) and is not a body signature. An unauthenticated attacker who knows the public webhook URL can POST forged inbound messages with an attacker-chosen sender identity and arbitrary text, causing the bot owner's agent to process attacker-controlled input and treat the attacker as a trusted platform sender.

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Meta Information

Published
2026-09-04
Last Modified
2026-09-04
Generated
2026-09-04
AI Q&A
2026-09-04
EPSS Evaluated
N/A
NVD
CVE-2026-85621
EUVD
EUVD-2026-71228

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
lobehub lobechat to 2.2.15 (inc)
lobehub chat-adapter-qq 2.2.15
lobehub chat-adapter-feishu 2.2.15

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-345 The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.

Attack-Flow Graph

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Executive Summary

CVE-2026-85621 is a webhook signature verification bypass in LobeChat version 2.2.1. The QQ and Feishu adapters fail to properly verify inbound webhook signatures. The QQ adapter performs no Ed25519 signature verification, while the Feishu adapter only optionally checks a static token that is disabled by default. This allows unauthenticated attackers to forge messages with spoofed sender identities and arbitrary content.

Detection Guidance

To detect this vulnerability, inspect the LobeChat deployment for unauthenticated webhook routes (/api/agent/webhooks/:platform) and verify if QQ or Feishu adapters are configured without signature verification. Check logs for POST requests to these endpoints with forged payloads. Use tools like curl to test webhook endpoints for missing authentication headers or tokens.

Impact Analysis

An attacker could send crafted messages to the bot, tricking it into processing attacker-controlled input as if it came from a trusted platform sender. This may lead to unauthorized agent execution, prompt injection, potential data leaks, or compromised bot behavior. Unauthorized model usage is also possible.

Compliance Impact

This vulnerability could lead to unauthorized data processing or leaks, violating GDPR principles like data integrity and confidentiality. For HIPAA, it may risk exposing protected health information if the bot handles such data. Compliance requires proper access controls and audit trails, which this flaw undermines.

Mitigation Strategies

Upgrade LobeChat to the latest version where signature verification is enforced for all adapters. Configure mandatory Ed25519 signature verification for QQ and static token verification for Feishu. Ensure tokens are not optional and use constant-time comparisons. Disable unauthenticated webhook routes if possible.

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