What’s Vulnerable › Vulnerabilities

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

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-10-12 · updated 2026-10-26
• Weakness: CWE-451

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 products

• Npm Better-Auth: from 1.3.8-beta.3 before 1.7.0-rc.3 — fixed in 1.7.0-rc.3
• better-auth: from 1.3.8-beta.3 before 1.7.0-rc.3 — fixed in 1.7.0-rc.3

How to fix

Upgrade to a fixed version: Npm Better-Auth 1.7.0-rc.3; better-auth 1.7.0-rc.3. Check the vendor advisory for mitigations.

References

• https://github.com/better-auth/better-auth/security/advisories/GHSA-q84f-53jg-9ppm
• https://www.vulncheck.com/advisories/better-auth-1.3.8-beta.3-before-1.7.0-rc.3-device-authorization-phishing-via-device

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