CVE Catalog

CVE-2026-110863

HighCVSS 8.1
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.27%

18th percentile - higher than 18% of all known CVEs

Summary

Better Auth @better-auth/sso from 1.7.0-rc.2 before 1.7.3 contains an authentication bypass vulnerability that allows authenticated users to sign in as other users by registering a personal SSO provider. An attacker can copy a legitimate provider's OIDC issuer or SAML entity ID and assert a victim's subject or NameID, because account lookup ignores providerId, creating sessions for victim accounts.

Risk Assessment

An authenticated user can take over other accounts' sessions, gaining access to their data and permissions in the application.

Recommendation

Update @better-auth/sso to version 1.7.3 or later. Restrict the ability to register personal SSO providers and verify providerId matching during account lookup.

Related vulnerabilities

Original NVD description (English source)

Better Auth @better-auth/sso from 1.7.0-rc.2 before 1.7.3 contains an authentication bypass vulnerability that allows authenticated users to sign in as other users by registering a personal SSO provider. Attackers can copy a legitimate provider's OIDC issuer or SAML entity ID and assert a victim's subject or NameID, because account lookup ignores providerId, creating sessions for victim accounts.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS