CVE-2026-39411 is a medium-severity (CVSS 5) Improper Authentication vulnerability in @lobehub/lobehub. A fix is available for @lobehub/lobehub — see the affected versions and patch details below.
LobeHub has an unauthenticated authentication bypass on `webapi` routes via forgeable `X-lobe-chat-auth` header
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-39411.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-39411 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
How broadly this vulnerability is actually deployed: weekly install volume shows current usage, and reverse-dependency count shows how many other packages break if it stays unpatched.
@lobehub/lobehubnpmDescription
Summary
The webapi authentication layer trusts a client-controlled X-lobe-chat-auth header that is only XOR-obfuscated, not signed or otherwise authenticated. Because the XOR key is hardcoded in the repository, an attacker can forge arbitrary auth payloads and bypass authentication on protected webapi routes.
Affected routes include:
POST /webapi/chat/[provider]GET /webapi/models/[provider]POST /webapi/models/[provider]/pullPOST /webapi/create-image/comfyui
Details
The frontend creates X-lobe-chat-auth by XOR-obfuscating JSON with the static key LobeHub · LobeHub, and the backend reverses that operation and treats the decoded JSON as trusted authentication data.
The backend then accepts any truthy apiKey field in that decoded payload as sufficient authentication. No real API key validation is performed in this path.
As a result, an unauthenticated attacker can forge payloads such as:
{"apiKey":"x"}
or
{"userId":"victim-user-123","apiKey":"x"}
and access webapi routes as an authenticated user.
Confirmed PoC The following forged header was generated directly from the published XOR key using payload {"apiKey":"x"}:
X-lobe-chat-auth: N00DFSE+B1ngjQI0TR8=
That header decodes server-side to:
{"apiKey":"x"}
A simple request is:
-H 'X-lobe-chat-auth: N00DFSE+B1ngjQI0TR8=' ```
If the deployment has OPENAI_API_KEY configured, the request should succeed without a real login and return the provider model list.
A forged impersonation payload also works conceptually:
``` {"userId":"victim-user-123","apiKey":"x"} ```
### Impact
This is an unauthenticated authentication bypass.
An attacker can:
1. access protected webapi routes without a valid session
2. spend the deployment's server-side model provider credentials when env keys like OPENAI_API_KEY are configured
3. impersonate another user's userId for routes that load per-user provider configuration
4. invoke privileged backend model operations such as chat, model listing, model pulls, and ComfyUI image generation
### Root Cause
The core issue is trusting unsigned client-supplied auth data:
1. the auth header is only obfuscated, not authenticated
2. the obfuscation key is hardcoded and recoverable from the repository
3. the decoded apiKey field is treated as sufficient authentication even though it is never validated in this code path
4. Suggested Remediation
5. Stop treating X-lobe-chat-auth as an authentication token.
6. Remove the apiKey truthiness check as an auth decision.
7. Require a real server-validated session, OIDC token, or validated API key for all protected webapi routes.
8. If a client payload is still needed, sign it server-side with an HMAC or replace it with a normal session-bound backend lookup.
9. Affected Products
Ecosystem: npm
Package name: @lobehub/lobehub
Affected versions: <= 2.1.47
Patched versions: 2.1.48
Severity
Moderate
Vector String
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L
Weaknesses
CWE-287: Improper Authentication
CWE-345: Insufficient Verification of Data Authenticity
CWE-290: Authentication Bypass by Spoofing
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 📦npm | @lobehub/lobehub | all versions | 2.1.48npm install @lobehub/lobehub@2.1.48 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for @lobehub/lobehub, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update @lobehub/lobehub to 2.1.48 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-39411 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-39411 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-39411. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-39411 in your dependencies?
O3 Security finds CVE-2026-39411 across npm dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.