Is CVE-2026-63438 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-63438 being exploited in the wild.

How severe is CVE-2026-63438?

Critical severity, with a CVSS score of 9.8, published 6 November 2026.

Is there a fix for CVE-2026-63438?

Yes: fixed in 8.0.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-63438 attacked?

It is attacked over the network.

Am I affected by CVE-2026-63438?

Check whether you run Bubka 2FAuth at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-63438: 2FAuth reverse-proxy authentication bypass leading to account creation

CVE-2026-63438 · Severity: critical · CVSS 9.8 · Published 2026-11-06

2FAuth is a web application that stores and manages two-factor authentication codes for user accounts. When configured to trust authentication headers from a reverse proxy, versions before 8.0.0 accept those headers from any client without verifying the request came through a legitimate proxy, allowing an attacker to create a new administrator account or take over existing accounts and steal their 2FA secrets.

Technologies: Bubka 2FAuth. Vendors: Bubka.

Quick answers

Is CVE-2026-63438 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-63438 being exploited in the wild.
How severe is CVE-2026-63438?: Critical severity, with a CVSS score of 9.8, published 6 November 2026.
Which products and versions are affected?: Bubka 2FAuth before 8.0.0.
Is there a fix for CVE-2026-63438?: Yes: fixed in 8.0.0. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-63438 attacked?: It is attacked over the network.
Am I affected by CVE-2026-63438?: Check whether you run Bubka 2FAuth at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: 8.0.0

Technical details

The vulnerability exists in the RemoteUserProvider::retrieveById() method when AUTHENTICATION_GUARD is set to reverse-proxy-guard. The ReverseProxyGuard fails to validate that incoming authentication headers originated from a trusted proxy, allowing unauthenticated remote clients to forge authentication claims. On a fresh instance, this results in automatic promotion of the first created account to administrator; on existing instances, attackers can impersonate users and modify their email address to redirect password resets or 2FA secret exfiltration.

Affected products

Bubka 2FAuth before 8.0.0

Timeline

2026-11-06: disclosed

References

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