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TI-2025-43517 Aliases CVE-2025-71401GHSA-569q-mpph-wgww

better-auth before 1.4.2 basePath Modification DoS

Priority MEDIUM 40CWE-770Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
None
Impact type
Denial of service
Confidentiality · integrity · availability
High · High · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-770.

Summary

better-auth (npm) before 1.4.2 allows an external request to configure baseURL when it is not otherwise defined (e.g., BETTER_AUTH_URL is unset). An attacker able to make the very first request to the server after startup can poison the router's base path, causing all routes to return 404 for all users (denial of service). The issue is not reachable when baseURL is explicitly configured or on typical managed hosting platforms.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00455 39th percentileScored 2026-11-07
Fix Fixed better-auth (better-auth): 1.4.2better-auth (npm): 1.4.2

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

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 1.4.21.4.2Patch availableCNA
—better-auth (npm)before 1.4.21.4.2Patch availableGHSA-569q-mpph-wgww
  • better-auth Vendorbetter-auth Affected before 1.4.2 Fixed in 1.4.2 Patch available CNA
  • better-auth (npm) Vendor— Affected before 1.4.2 Fixed in 1.4.2 Patch available GHSA-569q-mpph-wgww

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

  • Fix · CNA better-auth (better-auth) Fixed in 1.4.2
  • Fix · GHSA-569q-mpph-wgww better-auth (npm) Fixed in 1.4.2 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-71401
  2. 2026-10-03 Alias added: GHSA-569q-mpph-wgww

References

Advisory 2

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