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TI-2026-86111 Aliases CVE-2026-63438

Reverse proxy guard in 2FAuth accepts unauthenticated user headers

Priority MEDIUM 43CWE-287Published · Updated

Key facts

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

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-287.

Summary

Bubka 2FAuth is affected before version 8.0.0. Improper authentication (CWE-287) lets the reverse proxy guard accept authentication headers from a client that did not pass through a trusted proxy, which creates accounts for unknown users, promotes the first account to administrator, and syncs the account email from a configured mail header. An unauthenticated remote attacker can create an administrator on a fresh instance or impersonate a known account and redirect its email, exposing 2FA secrets and administrative functions.

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

Description from the CNA

2FAuth is a web app to manage Two-Factor Authentication (2FA) accounts and generate their security codes. Prior to 8.0.0, when AUTHENTICATION_GUARD=reverse-proxy-guard accepts authentication headers from a client that did not pass through a trusted proxy, RemoteUserProvider::retrieveById() creates an account for an unknown REMOTE_USER, promotes the first created account to administrator, and synchronizes the account email from the configured mail header. An unauthenticated remote client can therefore create an administrator on a fresh instance or impersonate and redirect email for a known account, exposing 2FA secrets and administrative functions. This issue is fixed in version 8.0.0.

Why it matters now

EPSS 0.00505 43rd percentileScored 2026-11-07
Fix Fixed 2FAuth (Bubka): 8.0.0

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

VendorProductAffected versionsFixed inStatusSource
Bubka2FAuthbefore 8.0.08.0.0Patch availableCNA
  • 2FAuth VendorBubka Affected before 8.0.0 Fixed in 8.0.0 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:2fauth:2fauth:*:*:*:*:*:*:*:*——Bubka
  • cpe:2.3:a:2fauth:2fauth:*:*:*:*:*:*:*:* Versions — — ·Bubka

Remediation

Upgrade 2FAuth to version 8.0.0, the fixed version for Bubka 2FAuth.

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

  • Fix · CNA 2FAuth (Bubka) Fixed in 8.0.0

Timeline

  1. 2026-11-06 Threatist record created from CVE-2026-63438

References

Other 5

  • TI-2026-24670 2FAuth has Blind SSRF in image parameter allows internal network access and more CVSS 4.0HIGH 7.8
  • TI-2024-35258 2FAuth vulnerable to Server Side Request Forgery + URI validation bypass in 2fauth /api/v1/twofaccounts/preview CVSS 3.1HIGH 7.5
  • TI-2025-28827 A group deletion race condition in 2FAuth v5.5.0 causes data inconsistencies and orphaned… CVSS 3.1MEDIUM 6.5
  • TI-2024-35257 2FAuth vulnerable to stored cross-site scripting via SVG upload and direct access render CVSS 3.1MEDIUM 6.1
  • TI-2023-18610 Cross-Site Scripting (XSS) at Account creation in 2FAuth CVSS 3.1MEDIUM 6.1
  • TI-2026-86112 2FAuth reverse proxy guard trusts client-supplied identity headers CVSS 3.1CRITICAL 9.8
See all 9 →

Sources

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