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CVE-2026-63438

9.8 criticalEPSS 0.5%

Critical (9.8) in bubka 2fauth. EPSS 0.5% estimated probability of exploitation activity in the next 30 days.

On this page
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.

Severity

CVSS 3.1

9.8 critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS
0.5% estimated probability of exploitation activity in the next 30 days; 44th percentile. Scored 2026-11-10. A forecast for this CVE across the internet, not for your own systems.
CWE
CWE-287 Improper Authentication
OWASP Top 10
A07:2025 Authentication Failures
Published
NVD analysis
Awaiting analysis
Record from
the NVD, synced

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Affected

Versions

From the CNA's record in the CVE List.

ProductAffected
Bubka 2FAuth< 8.0.0

Attack patterns (CAPEC)

  • CAPEC-22 Exploiting Trust in Client Likelihood: High · Severity: High
  • CAPEC-57 Utilizing REST's Trust in the System Resource to Obtain Sensitive Data Likelihood: Medium · Severity: Very High
  • CAPEC-94 Adversary in the Middle (AiTM) Likelihood: High · Severity: Very High
  • CAPEC-114 Authentication Abuse Severity: Medium
  • CAPEC-115 Authentication Bypass Severity: Medium
  • CAPEC-151 Identity Spoofing Likelihood: Medium · Severity: Medium
  • CAPEC-194 Fake the Source of Data Severity: Medium
  • CAPEC-593 Session Hijacking Likelihood: High · Severity: Very High
  • CAPEC-633 Token Impersonation Severity: Medium
  • CAPEC-650 Upload a Web Shell to a Web Server Severity: High

The attack patterns MITRE's CAPEC relates to this record's weaknesses, as MITRE names them. Credits.

References

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