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© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2026-53512

39
FAUCET Score

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.

First published: Jul 15, 2026Last modified: Jul 15, 2026

Impacted Technologies

VendorProductVersion(s)CPE
< 1.6.11CPE matchmatch criteria
cpe:2.3:a:better-auth:better_auth:*:*:*:*:*:node.js:*:*

CVSS Data

CVSS version used by this source: 4.0

9.1CRITICAL

CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Attack Vector
NETWORK
Attack Complexity
LOW
Attack Requirements
PRESENT
Privileges Required
NONE
User Interaction
NONE
VS Confidentiality
HIGH
VS Integrity
HIGH
VS Availability
NONE
SS Confidentiality
NONE
SS Integrity
NONE
SS Availability
NONE
Exploit Maturity
NOT_DEFINED
CvssVersion
4.0

Exploit Intelligence

EPSS Score
0.21%
Probability of exploitation in next 30 days
EPSS Percentile
11.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0021 is in the 0th percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
npmpatch availablevia ghsa
Product: better-authFixed in: 1.6.11

Vendor Advisories (1)

npmGHSA-pw9m-5jxm-xr6hcritical

Better Auth: OAuth refresh-token replay via missing client authentication on oidc-provider and mcp plugins

Jul 7, 2026

References

github.com / better-auth/better-auth/commit/1f2ff4215c4affff0b140b0c0a712c0dde35659c
Patch
github.com / better-auth/better-auth/pull/9576
Issue TrackingPatch
github.com / better-auth/better-auth/releases/tag/v1.6.11
Release Notes
github.com / better-auth/better-auth/security/advisories/GHSA-pw9m-5jxm-xr6h
MitigationVendor Advisory