CVE-2026-110863GHSA-mx9r-x6ww-qjw9
Better Auth @better-auth/sso before 1.7.3 Authentication Bypass via Personal SSO Providers
better-auth sso
CVSS
8.6HighExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.27%Chance of exploitation activity in the next 30 days, higher than 18% of CVEs. Scored 23 Oct 2026FIRST EPSS
What fixes it
- 1.7.3ssoCVE List
A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.
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.
Text from CVE List
Affected versions 1
- ssoaffected: 1.7.0-rc.2 before 1.7.3CVE List