Vulnerability · Published Oct 12, 2026 · Assigned by VulnCheck

CVE-2026-109346better-auth 1.3.8-beta.3 before 1.7.0-rc.3 Device Authorization Phishing via /device

High 8.1

In plain English

A high-severity security flaw in better-auth from better-auth. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 20% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)8.1High

Exploit odds (30 days)0.3%top 79.6% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
npm	better-auth	1.7.0-rc.3	GHSA-q84f-53jg-9ppm

Affected products (as reported)

Vendor	Product	Versions
better-auth	better-auth	1.3.8-beta.3 – before 1.7.0-rc.3

Weakness: CWE-451 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N

References

GitHub Security Advisory (GHSA-q84f-53jg-9ppm) vendor-advisory
VulnCheck Advisory: better-auth 1.3.8-beta.3 before 1.7.0-rc.3 Device Authorization Phishing via /device third-party-advisory