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TI-2026-74554 Aliases CVE-2026-110864

Authentication bypass in Better Auth OAuth Proxy plugin allows account takeover

Priority MEDIUM 41CWE-287Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Attack requirements
Present
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-287.

Summary

Better Auth from 1.5.0-beta.12 before 1.7.7 contains an authentication bypass in the OAuth Proxy plugin. When the proxy shares the global secret and cookie-stored state is used, an unauthenticated remote attacker can forge encrypted profiles and sign in as other users, taking over accounts through implicit linking. The flaw is classified as CWE-287 (Improper Authentication).

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

Better Auth from 1.5.0-beta.12 before 1.7.7 contains an authentication bypass vulnerability in the OAuth Proxy plugin that allows unauthenticated attackers to sign in as other users by forging encrypted profiles. When the proxy shares the global secret and cookie-stored state is used, attackers can obtain encrypted state for a fake profile with a victim's verified email to take over the account via implicit linking.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00288 21st percentileScored 2026-11-07
Fix Fixed better-auth (better-auth): 1.7.7

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

VendorProductAffected versionsFixed inStatusSource
better-authbetter-auth1.5.0-beta.12 to before 1.7.71.7.7Patch availableCNA
  • better-auth Vendorbetter-auth Affected 1.5.0-beta.12 to before 1.7.7 Fixed in 1.7.7 Patch available CNA

CPE names Threatist (inferred) · 1

Inferred from how NVD named this product before; not given by a source.

CPEVersionsRoleVendor
cpe:2.3:a:better-auth:better_auth:*:*:*:*:*:*:*:*——better-auth
  • cpe:2.3:a:better-auth:better_auth:*:*:*:*:*:*:*:* Versions — — ·better-auth

Remediation

Upgrade better-auth to version 1.7.7 or later, which fixes this issue.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA better-auth (better-auth) Fixed in 1.7.7

Fixed in the same release

Records fixed by the same vendor advisory or release, as the CNA lists them.

  • Release ·

    better-auth 1.7.7

    3 records Highest priority Priority MEDIUM 2 MEDIUM, 1 LOW

    Other records, highest priority first

    • TI-2026-74552 Authentication bypass in Better Auth Magic Link verificationPriority MEDIUM 48
    • TI-2026-74551 Race condition in Better Auth rate limiting allows limit bypassPriority LOW 27
    Show all 3 records →

Timeline

  1. 2026-10-15 Threatist record created from CVE-2026-110864
  2. 2026-10-15 CISA SSVC decision points changed
  3. 2026-10-15 Priority changed: MEDIUM → LOW
  4. 2026-10-16 Priority changed: LOW → MEDIUM

References

Advisory 1

  • 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
See all 39 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences