Read the docs
TI-2026-84923 Aliases CVE-2026-121802GHSA-hv45-wgqh-c9j5

Unchecked state signing in @better-auth/expo enables account takeover

Priority MEDIUM 47CWE-346Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-346.

Summary

@better-auth/expo before 1.7.16 signs a caller-supplied state value without checking that the server issued it (CWE-346). An unauthenticated remote attacker can change the email address of any account, and other account takeover outcomes are possible.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

Description from the CNA

@better-auth/expo before 1.7.16 allows certain account-takeover outcomes (e.g., unauthenticated changes of any account's email address), because it signs a caller-supplied state value without checking whether that value had been issued by the server. NOTE: the application secret must be rotated after updating to a fixed version.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00203 10th percentileScored 2026-11-07
Fix Fixed Better Auth (better-auth): 1.7.16

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

VendorProductAffected versionsFixed inStatusSource
better-authBetter Authbefore 1.7.161.7.16Patch availableCNA
  • Better Auth Vendorbetter-auth Affected before 1.7.16 Fixed in 1.7.16 Patch available CNA

Remediation

Update Better Auth to version 1.7.16. After updating to a fixed version, rotate the application secret.

Written with Claude Haiku 5.5 from the sources below · 2026-11-06

  • Fix · CNA Better Auth (better-auth) Fixed in 1.7.16

Timeline

  1. 2026-11-04 Threatist record created from CVE-2026-121802
  2. 2026-11-04 Alias added: GHSA-hv45-wgqh-c9j5
  3. 2026-11-05 Priority changed: MEDIUM → LOW
  4. 2026-11-06 Fix available: better-auth/Better [email protected] · CNA
  5. 2026-11-06 CISA SSVC decision points changed
  6. 2026-11-06 Priority changed: LOW → MEDIUM

References

Other 3

  • 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