CVE-2026-53517
HIGHBetter Auth OAuth Provider < 1.6.11 - Refresh Token Replay Race Condition
Title source: manualDescription
Better Auth is an authentication and authorization library for TypeScript. From 1.4.8-beta.7 until 1.6.11, the @better-auth/oauth-provider POST /oauth2/token endpoint on the refresh_token grant performs a non-atomic read, validate, revoke, and mint sequence on the oauthRefreshToken row, allowing concurrent requests with the same parent refresh token to pass the revoked check and create forked refresh-token families; the vulnerable range also includes embedded better-auth plugin versions before 1.6.0. This issue is fixed in version 1.6.11.
References (3)
Core 3
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/better-auth/better-auth/security/advisories/GHSA-392p-2q2v-4372
X_Refsource_Misc x_refsource_misc
https://github.com/better-auth/better-auth/commit/c6918ecc9e3a75892169415d7f6c95b591b6a52d
X_Refsource_Misc x_refsource_misc
https://github.com/better-auth/better-auth/releases/tag/v1.6.11
Scores
CVSS v3
8.1
EPSS
0.0024
EPSS Percentile
15.3%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
total
Details
CWE
CWE-362
CWE-367
Status
published
Products (7)
@better-auth/oauth-provider
>= 1.6.0, < 1.6.11
better-auth/better-auth
>= 1.4.8-beta.7, < 1.6.0
better-auth/better-auth\/oauth-provider
1.6.0 - 1.6.11
better-auth/better_auth
1.4.8 (2 CPE variants)
better-auth/better_auth
1.4.9 - 1.6.11
better-auth/oauth-provider
1.6.0 - 1.6.11npm
npm/better-auth
1.4.8-beta.7 - 1.6.0npm
Published
Jul 15, 2026
Tracked Since
Jul 15, 2026