Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, the legacy oidcProvider and mcp plugins expose OAuth token endpoints whose refresh_token grant authenticates only possession of the bound refreshToken row and matching client_id, without verifying the confidential client's client_secret, allowing an attacker with a valid refresh_token to mint access tokens and rotated refresh tokens through /api/auth/oauth2/token or /api/auth/mcp/token. The @better-auth/oauth-provider package is not affected. This issue is fixed in version 1.6.11.
CVE-2026-53512
CRITICALNVD 9.19.1—
EchelonGraph scoreMEDIUM confidence
This critical-severity CVE scores 9.1 under NVD CVSS v3. EPSS exploit probability: 0.3%, top 80% 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, nvd
9.1
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
- High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS: 0%CVSS: 9.1Exploit: NoneExposed: 0
No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.
- CVSS v3
- 9.1
- EG Score
- 9.1(medium)
- EG Risk
- 56(Track)EG Risk 56/100SSVC: 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 computedSeverity91% × 45%Exploitation0% × 40%Automatability100% × 15%Action: Routine — remediate on your standard cadence. - EPSS
- 19.6%
- KEV
- Not listed
Published
July 7, 2026
Last Modified
July 21, 2026
Advisory Details (4)
Auto-updated Jul 15, 2026Patch available. Sources: github, github_commit, github_pr, github_release.
github Patch Available
OAuth refresh-token replay via missing client authentication on oidc-provider and mcp plugins · Advisory · better-auth/better-auth · GitHub
https://github.com/better-auth/better-auth/security/advisories/GHSA-pw9m-5jxm-xr6hgithub_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_pr
fix(oidc-provider, mcp): authenticate confidential clients on refresh_token grant
Fix merged in better-auth/better-auth PR #9576 on 2026-05-12 — awaiting tagged release
https://github.com/better-auth/better-auth/pull/9576github_commit
commit 1f2ff4215c4a (better-auth/better-auth)
Fix landed in better-auth/better-auth commit 1f2ff4215c4a — awaiting tagged release
https://github.com/better-auth/better-auth/commit/1f2ff4215c4affff0b140b0c0a712c0dde35659cVendor Advisories for CVE-2026-53512(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Affected Packages
(1 across 1 ecosystem)
npm(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| better-auth | — | 1.6.11 | — |
Weakness Classification(4)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 10× in last 7d / 12× 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 14:31 UTCEPSS rescore
- 2026-07-19 14:31 UTCEPSS rescore
- 2026-07-19 03:43 UTCEG score recompute
- 2026-07-19 02:29 UTCEPSS rescore
- 2026-07-18 10:04 UTCEPSS rescore
- 2026-07-16 17:03 UTCEPSS rescore
- 2026-07-15 17:28 UTCMITRE cvelistV5CVSS v4 → 9.1
- 2026-07-07 20:27 UTCEG score recompute
Related CVEs(same CWE)
Frequently asked(5)
What is CVE-2026-53512?
CVE-2026-53512 is a critical vulnerability published on July 7, 2026. Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, the legacy oidcProvider and mcp plugins expose OAuth token endpoints whose refreshtoken grant authenticates only possession of the bound refreshToken row and matching clientid, without verifying the…
When was CVE-2026-53512 disclosed?
CVE-2026-53512 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-2026-53512 actively exploited?
CVE-2026-53512 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 19.6% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-53512?
CVE-2026-53512 has a CVSS v3 base score of 9.1 (NVD).
How do I remediate CVE-2026-53512?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-53512, 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-2026-53512
Is Your Infrastructure Affected by CVE-2026-53512?
EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.