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
HIGHPre-NVD 8.18.1—
EchelonGraph scoreMEDIUM confidence
This high-severity CVE scores 8.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.4%, top 65% of all CVEs by exploit prediction. 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).
Triggered by: NVD CVSS baseline
Sources: epss, secondary
8.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 8.1Exploit: NoneExposed: 0
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(medium)
- EG Risk
- 37(Track)EG Risk 37/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity81% × 45%Exploitation0% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 34.5%
- KEV
- Not listed
Published
July 7, 2026
Last Modified
July 21, 2026
Advisory Details (3)
Auto-updated Jul 15, 2026Patch available. Sources: github_commit, github_release, github.
github Patch Available
@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-4372github_release Patch Available
v1.6.11
Patch available: better-auth/better-auth v1.6.11
https://github.com/better-auth/better-auth/releases/tag/v1.6.11github_commit
commit 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.
Affected Packages
(2 across 1 ecosystem)
npm(2)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| better-auth | — | 1.6.0 | — |
| @better-auth/oauth-provider | — | 1.6.11 | — |
Weakness Classification(2)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 7× in last 7d / 8× 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.
- 2026-07-23 03:19 UTCEG score recompute
- 2026-07-22 14:08 UTCEPSS rescore
- 2026-07-21 15:25 UTCEPSS rescore
- 2026-07-20 17:08 UTCEPSS rescore
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-16 17:03 UTCEPSS rescore
- 2026-07-07 21:13 UTCEG score recompute
Related CVEs(same CWE)
Same CWE
10 shownCWE-362
Frequently asked(5)
What is CVE-2026-53517?
CVE-2026-53517 is a high vulnerability published on July 7, 2026. 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…
When was CVE-2026-53517 disclosed?
CVE-2026-53517 was first published in the National Vulnerability Database on July 7, 2026, with the most recent update on July 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-53517 actively exploited?
CVE-2026-53517 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 34.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-53517?
CVE-2026-53517 has a CVSS v3 base score of 8.1 (NVD).
How do I remediate CVE-2026-53517?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53517, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-53517
Is Your Infrastructure Affected by CVE-2026-53517?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.