TI-2026-71162 Aliases CVE-2026-109346 GHSA-v9c8-wq66-wf8g

UI misrepresentation in better-auth device flow enables phishing

LOW 39CWE-451Published 2026-10-12 · Updated 2026-10-26

Key facts

Attack vector: Network
Privileges required: None
User interaction: Active
Attack complexity: Low
Attack requirements: None
Impact type: Spoofing
Confidentiality · integrity · availability: High · High · None
Fix status: Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-451.

Summary

better-auth from 1.3.8-beta.3 before 1.7.0-rc.3 has a UI misrepresentation flaw in the deviceAuthorization plugin, where GET /device omits the requesting client_id and scope (CWE-451). An unauthenticated remote attacker can start a device request and trick a signed-in user into approving it, which gives the attacker a live session token. The attack requires the user to approve the request.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

better-auth from 1.3.8-beta.3 before 1.7.0-rc.3 contains a UI misrepresentation vulnerability in the deviceAuthorization plugin because GET /device omits the requesting client_id and scope. Attackers can start a device request via /device/code, trick signed-in users into approving the code, then redeem it at /device/token for a live session token.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.00278 20th percentileScored 2026-11-07

Fix Fixed better-auth (better-auth): 1.7.0-rc.3

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	better-auth	1.3.8-beta.3 to before 1.7.0-rc.3	1.7.0-rc.3	Patch available	CNA

better-auth Vendorbetter-auth Affected 1.3.8-beta.3 to before 1.7.0-rc.3 Fixed in 1.7.0-rc.3 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

Update better-auth to version 1.7.0-rc.3, the fixed version.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Fix · CNA better-auth (better-auth) Fixed in 1.7.0-rc.3

Timeline

2026-10-12 Threatist record created from CVE-2026-109346
2026-10-12 Alias added: GHSA-v9c8-wq66-wf8g
2026-10-13 Priority changed: MEDIUM → LOW
2026-10-26 CISA SSVC decision points changed

References

Advisory 1

GitHub Security Advisory (GHSA-q84f-53jg-9ppm)

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