CVE-2026-110863

Better Auth @better-auth/sso before 1.7.3 Authentication Bypass via Personal SSO Providers

Published Oct 14, 2026 CVSS 4.0 · 8.6 High EPSS < 1% KEV · Not listed
Description
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description 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.
Title Better Auth @better-auth/sso before 1.7.3 Authentication Bypass via Personal SSO Providers
First Time appeared Better-auth
Better-auth better-auth\/sso
Weaknesses CWE-287
CPEs cpe:2.3:a:better-auth:better-auth\/sso:*:*:*:*:*:*:*:*
Vendors & Products Better-auth
Better-auth better-auth\/sso
References
Metrics cvssV3_1

{'score': 8.1, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N'}

cvssV4_0

{'score': 8.6, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
VulnCheck
Published
Updated
Oct 16, 2026, 5:14 PM
Reserved
Oct 14, 2026, 10:18 PM
Status
Awaiting Analysis
Published
Oct 14, 2026, 11:17 PM
Modified
Oct 16, 2026, 6:17 PM