Auth bypass in Better-Auth
CVE-2026-45337
Better Auth is an authentication and authorization library for TypeScript. From 1.6.0 until 1.6.11, the deviceAuthorization plugin treats any authenticated session as the owner of any pending device code because GET /device does not claim the row and POST /device/approve and POST /device/deny short-circuit when userId is unset, allowing an authenticated attacker who learns a valid user_code to bind the polling device to the attacker's account or deny the legitimate flow. This issue is fixed in version 1.6.11.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.6 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:L.
EPSS exploit prediction
EPSS: 0.002 (11.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 11th percentile — 11.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000
Affected products
- Better-Auth — versions >= 1.6.0, < 1.6.11
- Better-Auth Better Auth
Weakness classification (CWE)
References
- github.com/better-auth/better-auth/security/advisories/GHSA-cq3f-vc6p-68fh (Mitigation, Vendor Advisory)
- github.com/better-auth/better-auth/pull/9573 (Patch, Issue Tracking)
- github.com/better-auth/better-auth/commit/99a254a79b59d5a3f5ca2123260118cddb5be… (Patch)
- github.com/better-auth/better-auth/releases/tag/v1.6.11 (Release Notes)
Frequently asked questions
- What is CVE-2026-45337?
- CVE-2026-45337 is a high-severity vulnerability in Better-Auth, classified under Improper Authorization. CVSS score: 7.6/10. Published 2026-07-15.
- How severe is CVE-2026-45337?
- High severity. CVSS v3 base score is 7.6 out of 10.