@better-auth/sso before 1.6.21 Account Takeover via SSO
Priority MEDIUM 40CWE-79Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Attack requirements
- None
- Impact type
- Cross-site scripting
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- Fixed
Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-79.
Summary
@better-auth/sso versions before 1.6.21 contain multiple authentication bypass vulnerabilities in SSO provider handling that allow attackers to sign in as arbitrary users. Attackers can exploit domain verification parsing mismatches, orphaned provider accounts, unbound SAML assertions, or reflected XSS on logout endpoints to gain unauthorized session access and account takeover.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00491 42nd percentileScored 2026-11-07
Fix Fixed sso (better-auth): 1.6.21, 1.7.0-beta.10
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| better-auth | sso | before 1.6.21 | 1.6.21 | Patch available | CNA |
| better-auth | sso | 1.7.0-beta.0 to before 1.7.0-beta.10 | 1.7.0-beta.10 | Patch available | CNA |
- sso Vendorbetter-auth Affected before 1.6.21 Fixed in 1.6.21 Patch available CNA
- sso Vendorbetter-auth Affected 1.7.0-beta.0 to before 1.7.0-beta.10 Fixed in 1.7.0-beta.10 Patch available CNA
Remediation
- Fix · CNA sso (better-auth) Fixed in 1.6.21
- Fix · CNA sso (better-auth) Fixed in 1.7.0-beta.10
Timeline
- 2026-10-02 Threatist record created from CVE-2026-67328
- 2026-10-03 Alias added: GHSA-8g2f-78cq-p655
References
More better-auth vulnerabilities
- TI-2025-38277 Better Auth: Unauthenticated API key creation through api-key plugin CVSS 4.0CRITICAL 9.3
- TI-2026-47627 better-auth SCIM 1.5.0 before 1.7.0-beta.4 Authorization Bypass CVSS 4.0HIGH 8.7
- TI-2025-20000 Beter Auth has an Open Redirect via Scheme-Less Callback Parameter CVSS 4.0MEDIUM 6.9
- TI-2026-13066 better-auth better-icons scan_project_icons/sync_icon path traversal CVSS 4.0MEDIUM 4.8
- TI-2026-79320 OAuth state accepted as Magic Link token in Better Auth CVSS 3.1CRITICAL 9.1
- TI-2026-74552 Authentication bypass in Better Auth Magic Link verification CVSS 4.0CRITICAL 9.3
Sources
- CVE-2026-67328 · CVE Program
- CVE-2026-67328 · NVD
- FIRST EPSS
- GHSA-8g2f-78cq-p655 · GitHub Advisory Database · CC BY 4.0
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