# CVE-2026-85621: LobeChat 2.2.1 Webhook Signature Verification Bypass QQ Feishu

> Unauthenticated attackers can bypass webhook signature verification in LobeChat to inject forged messages, impersonating trusted users to manipulate the AI agent.

- **Severity:** Medium 6.9 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 4 Sep 2026
- **Updated:** 8 Sep 2026
- **Also known as:** GHSA-627w-x4jq-g83v

## What is CVE-2026-85621?

CVE-2026-85621 is a medium-severity authentication bypass vulnerability in lobehub, published on 4 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official 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.

Weakness: CWE-345 (Insufficient Verification of Data Authenticity)

## Which versions are affected by CVE-2026-85621?


## How do I fix CVE-2026-85621?

No fix has been published for CVE-2026-85621 yet. Limit exposure of the affected software until one is available.

## Is CVE-2026-85621 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-85621 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-85621 and fix it if it is affected.

What it is: CVE-2026-85621 is a medium-severity authentication bypass vulnerability in lobehub, published on 4 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-85621 exists.

Affected product: lobehub. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-85621/ (Markdown: https://insights.sbomify.com/CVE-2026-85621/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-85621
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-85621
- OSV: https://osv.dev/vulnerability/CVE-2026-85621

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-85621/
Summaries are generated and may contain mistakes; the official description above is the record.