CVE-2026-109346 better-auth 1.3.8-beta.3 before 1.7.0-rc.3 Device Authorization Phishing via /device
Attackers can trick users into approving device authorization requests to steal session tokens due to missing client identification in the UI.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-109346?
CVE-2026-109346 is a high-severity vulnerability in better-auth, published on 12 Oct 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
better-auth from 1.3.8-beta.3 before 1.7.0-rc.3 contains a UI misrepresentation vulnerability in the deviceAuthorization plugin because GET /device omits the requesting client_id and scope. Attackers can start a device request via /device/code, trick signed-in users into approving the code, then redeem it at /device/token for a live session token.
Weakness: CWE-451
Which versions are affected by CVE-2026-109346?
2 open source packages ship an affected version, including better-auth.
| Package | Affected | Fixed in |
|---|---|---|
better-auth npm | From 1.3.8-beta.3 | 1.7.0-rc.3 |
better-auth npm | From 1.3.8-beta.3 | 1.7.0-rc.3 |
How do I fix CVE-2026-109346?
Upgrade better-auth to 1.7.0-rc.3 or later.
Is CVE-2026-109346 being exploited?
There is no known exploitation of CVE-2026-109346 in the wild and no public exploit code.
Sources
Also known as GHSA-q84f-53jg-9ppm, GHSA-v9c8-wq66-wf8g.