CVE-2026-53517Better Auth is an authentication and authorization library for TypeScript.
Updated under an hour ago ()
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It affects better-auth/oauth-provider and 1 other product. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 8.1 HIGH (v3.1, NVD)CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N
- Weakness (CWE)
- CWE-362, CWE-367
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Not given
- NVD analysis
- Analyzed
- Record last updated
- Jul 21, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
better-auth better-auth/oauth-provider better-auth:better-auth/oauth-provider | from 1.6.0 before 1.6.11 | NVD |
better-auth better_auth better-auth:better_auth | from 1.4.9 before 1.6.11; 1.4.8; 1.4.8 | NVD |
References
- https://github.com/better-auth/better-auth/commit/c6918ecc9e3a75892169415d7f6c95b591b6a52dpatch
- https://github.com/better-auth/better-auth/releases/tag/v1.6.11release-notes
- https://github.com/better-auth/better-auth/security/advisories/GHSA-392p-2q2v-4372mitigation, vendor-advisory
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.