TI-2026-74552 Aliases CVE-2026-110862

Authentication bypass in Better Auth Magic Link verification

MEDIUM 48CWE-287Published 2026-10-14 · Updated 2026-10-15

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Attack requirements: None
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 1.4.0-beta.18 before 1.7.7 contains an authentication bypass in its Magic Link flow. An unauthenticated remote attacker can reuse OAuth state values as Magic Link tokens to sign in as other users, obtaining sessions or creating falsely email-verified accounts. The weakness 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 1.4.0-beta.18 before 1.7.7 contains an authentication bypass vulnerability that allows unauthenticated attackers to sign in as other users by reusing OAuth state values as Magic Link tokens. Attackers can start an OAuth sign-in with a victim's email and submit the returned state to Magic Link verification, gaining sessions or creating falsely email-verified accounts.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00321 25th 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: Yes
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	better-auth	1.4.0-beta.18 to before 1.7.7	1.7.7	Patch available	CNA

better-auth Vendorbetter-auth Affected 1.4.0-beta.18 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.

CPE	Versions	Role	Vendor
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 the 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 · 2026-10-14
better-auth 1.7.7
3 records Highest priority Priority MEDIUM 2 MEDIUM, 1 LOW
Other records, highest priority first
- TI-2026-74554 Authentication bypass in Better Auth OAuth Proxy plugin allows account takeoverPriority MEDIUM 41
- TI-2026-74551 Race condition in Better Auth rate limiting allows limit bypassPriority LOW 27
Show all 3 records →

Timeline

2026-10-15 Threatist record created from CVE-2026-110862
2026-10-15 CISA SSVC decision points changed

References

Advisory 1

GitHub Security Advisory (GHSA-965c-763c-88jm)

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-2026-84923 Unchecked state signing in @better-auth/expo enables account takeover CVSS 3.1CRITICAL 9.1

See all 39 →

Sources

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