CVE-2026-110863 Better Auth @better-auth/sso before 1.7.3 Authentication Bypass via Personal SSO Providers
Authenticated users can hijack other accounts by registering a personal SSO provider with a copied issuer or entity ID, bypassing account lookup checks.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-110863?
CVE-2026-110863 is a high-severity authentication bypass vulnerability in better-auth sso, published on 14 Oct 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-287
Which versions are affected by CVE-2026-110863?
How do I fix CVE-2026-110863?
No fix has been published for CVE-2026-110863 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-110863 being exploited?
There is no known exploitation of CVE-2026-110863 in the wild and no public exploit code.
Sources
Also known as GHSA-47gc-4jpf-3mgv, GHSA-mx9r-x6ww-qjw9.