CVE-2026-53517 Better Auth OAuth Provider: Refresh Token Rotation Race Condition Allows Concurrent Replay and Token Family Forking

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 refreshtoken grant performs a non-atomic read, validate, revoke, and mint sequence on the oauthRefreshToken row, allowing...

@inkeep/agents-api (>=0.73.0, <=0.80.7), @inkeep/agents-cli (>=0.73.0, <=0.80.7) +5 more potentially affected by CVE-2026-53517 via @better-auth/oauth-provider (1.6.9)

@better-auth/oauth-provider NPM version 1.6.9 is affected by a known vulnerability. The following packages have a transitive dependency on @better-auth/oauth-provider and may be impacted: - @inkeep/agents-api =0.73.0, =0.73.0, =0.73.1, =0.73.0, =0.73.1, =0.73.1, =0.73.1, =0.80.7 Source cves:...

CVE-2026-53517

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 refreshtoken grant performs a non-atomic read, validate, revoke, and mint sequence on the oauthRefreshToken row, allowing...

EUVD-2026-44745

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 refreshtoken grant performs a non-atomic read, validate, revoke, and mint sequence on the oauthRefreshToken row, allowing...

CVE-2026-53517

CVE-2026-53517 affects Better Auth’s oauth-provider (and related memory adapter) prior to version 1.6.11. The POST /oauth2/token refresh_token flow performs a non-atomic read–validate–revoke–mint sequence on the oauthRefreshToken row, allowing concurrent requests with the same parent refresh toke...

@agentcorporation/server (>=0.3.3, <=0.3.13), @agentuity/auth (>=1.0.35, <=3.0.0-alpha.6) +120 more potentially affected by CVE-2026-53517 via better-auth (>=1.4.9, <=1.6.0-beta.0)

better-auth NPM version =1.4.9, =0.3.3, =1.0.35, =1.0.35, =1.0.35, =1.0.35, =1.0.35, =2026.324.0-canary.0, =0.0.2, =2026.501.0, =2026.501.0, =0.0.7, =1.4.21, =1.7.0, =2026.512.0-canary.0, =2.1.0, =2.1.1 and more Source cves: CVE-2026-53517 Source advisory: MEND:CVE-2026-53517...

CVE-2026-53517

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 refreshtoken grant performs a non-atomic read, validate, revoke, and mint sequence on the oauthRefreshToken row, allowing...

CVE-2026-45337

Better Auth (TypeScript library) vulnerability CVE-2026-45337 affects versions 1.6.0–1.6.10 in the deviceAuthorization plugin. The root cause is that the verification path does not claim ownership of the pending device code and the approve/deny checks short-circuit when userId is unset, allowing ...

CVE-2026-45337 Better Auth: Device authorization approve and deny accept any authenticated session while the user code is pending

Better Auth is an authentication and authorization library for TypeScript. From 1.6.0 until 1.6.11, the deviceAuthorization plugin treats any authenticated session as the owner of any pending device code because GET /device does not claim the row and POST /device/approve and POST /device/deny...

@agent-native/core (>=0.26.5, <=0.47.1), @automate.ax/components-core (>=0.1.3, <=0.3.1) +27 more potentially affected by CVE-2026-45337 via better-auth (>=1.6.0, <=1.6.10)

better-auth NPM version =1.6.0, =0.26.5, =0.1.3, =2.2.0, =2.2.0, =2.2.0, =2.2.0, =2.2.0, =2.2.0, =2.2.0, =2.2.0, =2.11.3, =0.73.0, =0.73.0, =0.73.1, =0.80.6 and more Source cves: CVE-2026-45337 Source advisory: MEND:CVE-2026-45337...

CVE-2026-45337 Better Auth: Device authorization approve and deny accept any authenticated session while the user code is pending

Better Auth is an authentication and authorization library for TypeScript. From 1.6.0 until 1.6.11, the deviceAuthorization plugin treats any authenticated session as the owner of any pending device code because GET /device does not claim the row and POST /device/approve and POST /device/deny...

CVE-2026-53514

Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, and in 1.6.14 and later when invitation IDs can be obtained outside the invited mailbox and requireEmailVerificationOnInvitation: true is not enabled, the organization plugin's acceptInvitation,...

CVE-2026-53514 Better Auth: Unauthorized invitation acceptance via unverified email match in organization plugin

Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, and in 1.6.14 and later when invitation IDs can be obtained outside the invited mailbox and requireEmailVerificationOnInvitation: true is not enabled, the organization plugin's acceptInvitation,...

EUVD-2026-44742

Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, and in 1.6.14 and later when invitation IDs can be obtained outside the invited mailbox and requireEmailVerificationOnInvitation: true is not enabled, the organization plugin's acceptInvitation,...

@agent-native/core (>=0.26.5, <=0.47.1), @agentcorporation/server (>=0.3.3, <=0.3.13) +148 more potentially affected by CVE-2026-53514 via better-auth (>=0.4.9-beta.7, <=1.6.10)

better-auth NPM version =0.4.9-beta.7, =0.26.5, =0.3.3, =1.0.35, =1.0.35, =1.0.35, =1.0.35, =1.0.35, =2026.324.0-canary.0, =0.0.2, =2026.501.0, =2026.501.0, =0.1.3, =0.0.7, =0.0.1, =1.2.5, =1.9.7 and more Source cves: CVE-2026-53514 Source advisory: MEND:CVE-2026-53514...

CVE-2026-53514 Better Auth: Unauthorized invitation acceptance via unverified email match in organization plugin

Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, and in 1.6.14 and later when invitation IDs can be obtained outside the invited mailbox and requireEmailVerificationOnInvitation: true is not enabled, the organization plugin's acceptInvitation,...

CVE-2026-53515 Better Auth: Privilege escalation via SSO provider registration: missing admin role check in @better-auth/sso

Better Auth is an authentication and authorization library for TypeScript. From 1.2.10 until 1.6.11, the @better-auth/sso plugin's POST /sso/register endpoint lets any organization member attach a new SSO provider to that organization because registerSSOProvider checks only for a membership row a...

CVE-2026-53515 Better Auth: Privilege escalation via SSO provider registration: missing admin role check in @better-auth/sso

Better Auth is an authentication and authorization library for TypeScript. From 1.2.10 until 1.6.11, the @better-auth/sso plugin's POST /sso/register endpoint lets any organization member attach a new SSO provider to that organization because registerSSOProvider checks only for a membership row a...

CVE-2026-53512 Better Auth: OAuth refresh-token replay via missing client authentication on oidc-provider and mcp plugins

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...

CVE-2026-53512

CVE-2026-53512 affects Better Auth versions prior to 1.6.11, where the legacy oidcProvider and mcp plugins expose OAuth2 token endpoints that validate refresh_token grants without requiring the confidential client’s client_secret. An attacker with a valid refresh_token and the corresponding publi...