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.
CVE-2026-53517
This high-severity CVE scores 8.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- High severity, but no confirmed exploitation yet
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 8.1
- EG Score
- 8.1(low)
- EPSS
- —
- KEV
- Not listed
Published
July 7, 2026
Last Modified
July 15, 2026
Advisory Details (3)
Auto-updated Jul 15, 2026@better-auth/oauth-provider: OAuth refresh-token rotation forks the token family on concurrent redemption · Advisory · better-auth/better-auth · GitHub
https://github.com/better-auth/better-auth/security/advisories/GHSA-392p-2q2v-4372v1.6.11
Patch available: better-auth/better-auth v1.6.11
https://github.com/better-auth/better-auth/releases/tag/v1.6.11commit c6918ecc9e3a (better-auth/better-auth)
Fix landed in better-auth/better-auth commit c6918ecc9e3a — awaiting tagged release
https://github.com/better-auth/better-auth/commit/c6918ecc9e3a75892169415d7f6c95b591b6a52dVendor Advisories for CVE-2026-53517(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 15× in last 7d / 18× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
- 2026-07-15 23:14 UTCEG score recompute
- 2026-07-15 11:49 UTCEG score recompute
- 2026-07-15 00:24 UTCEG score recompute
- 2026-07-14 13:00 UTCEG score recompute
- 2026-07-14 01:36 UTCEG score recompute
- 2026-07-13 14:11 UTCEG score recompute
- 2026-07-13 02:45 UTCEG score recompute
- 2026-07-12 15:20 UTCEG score recompute
- 2026-07-12 03:55 UTCEG score recompute
- 2026-07-11 16:30 UTCEG score recompute
- 2026-07-11 05:06 UTCEG score recompute
- 2026-07-10 17:42 UTCEG score recompute
- 2026-07-10 06:18 UTCEG score recompute
- 2026-07-09 18:53 UTCEG score recompute
- 2026-07-09 07:29 UTCEG score recompute
- 2026-07-08 20:04 UTCEG score recompute
- 2026-07-08 08:39 UTCEG score recompute
- 2026-07-07 21:13 UTCEG score recompute
Related CVEs(same CWE)
Frequently asked(4)
What is CVE-2026-53517?
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What is the CVSS score of CVE-2026-53517?
How do I remediate CVE-2026-53517?
Dependency Blast Radius
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