CVE-2026-53515

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

HIGH
7.1
CVSS Score
Published: July 15, 2026 at 05:27 PM UTC
Updated: July 21, 2026 at 03:49 PM UTC
2 products affected across 1 vendorAuth Better AuthBetter Auth /sso

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Severity
HIGH7.1
Exploit prediction
EPSS 0.4%
SSVC
No known exploit

Description

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 and does not require an owner or admin role, allowing attacker-controlled OIDC or SAML providers to drive /sso/callback/{providerId} organization provisioning. This issue is fixed in version 1.6.11.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 1.6.111.2.10 ≤ v < 1.6.11
Affected range stops below 1.6.11, so it looks safe — our inference, not a vendor statement
v < 1.6.11
Affected range stops below 1.6.11, so it looks safe — our inference, not a vendor statement

References (4)

x_refsource_CONFIRMMitigationVendor Advisory
Source: cverecord
https://github.com/better-auth/better-auth/security/advisories/GHSA-gv74-j8m3-fg5f
x_refsource_MISCIssue TrackingPatch
Source: cverecord
https://github.com/better-auth/better-auth/pull/9220
x_refsource_MISCRelease Notes
Source: cverecord
https://github.com/better-auth/better-auth/releases/tag/v1.6.11

SSVC — Action Prioritization

SSVCNo known exploitNot automatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.1HIGHGitHub_M
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
LOW
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusANALYZED
CWE
CWE-269CWE-285CWE-863

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