Is CVE-2026-63439 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-63439 being exploited in the wild.

How severe is CVE-2026-63439?

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

How is CVE-2026-63439 attacked?

It is attacked over the network, in a web application.

Am I affected by CVE-2026-63439?

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-2026-63439: 2FAuth reverse proxy authentication bypass

CVE-2026-63439 · Severity: critical · CVSS 9.8 · Published 2026-11-06

2FAuth is a web application that manages and stores Two-Factor Authentication accounts and security codes for users. When configured to authenticate requests through a reverse proxy (a common enterprise setup), versions prior to 8.0.0 fail to verify that requests actually come from the trusted proxy, allowing attackers to directly forge user identity headers and gain unauthorized access to any account including administrator accounts. This grants attackers access to all stored 2FA secrets and the ability to manage user accounts and application settings.

Technologies: Bubka 2FAuth. Vendors: Bubka.

Quick answers

Is CVE-2026-63439 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-63439 being exploited in the wild.
How severe is CVE-2026-63439?: Critical severity, with a CVSS score of 9.8, published 6 November 2026.
Which products and versions are affected?: Bubka 2FAuth prior to 8.0.0.
Is there a fix for CVE-2026-63439?: Yes: fixed in 8.0.0. Until then: Configure the TRUSTED_PROXIES environment variable to list only legitimate proxy IP addresses that should be trusted to set user identity headers, ensuring the reverse proxy itself is properly configured and its IP is whitelisted. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-63439 attacked?: It is attacked over the network, in a web application.
Am I affected by CVE-2026-63439?: 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

Configure the TRUSTED_PROXIES environment variable to list only legitimate proxy IP addresses that should be trusted to set user identity headers, ensuring the reverse proxy itself is properly configured and its IP is whitelisted.

Technical details

The ReverseProxyGuard authentication class reads user identity from HTTP headers (REMOTE_USER or custom AUTH_PROXY_HEADER_FOR_USER) without validating that the request originated from a configured trusted proxy, enabling header spoofing. An attacker with network access to the application can craft requests with forged identity headers to impersonate any user. The vulnerability is resolved in version 8.0.0 by enforcing trusted proxy validation via the TRUSTED_PROXIES environment variable.

Affected products

Bubka 2FAuth prior to 8.0.0

Timeline

2026-11-06: disclosed

References

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