CVE-2026-84831 Mandatory MFA bypass before enrollment
Attackers with valid passwords for unenrolled MFA accounts can bypass second-factor authentication and access privileged functionality in SEPPmail Secure Email Gateway.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-84831?
CVE-2026-84831 is a high-severity authentication bypass vulnerability in SEPPmail Secure Email Gateway (SEG), published on 3 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
SEPPmail Secure Email Gateway before 15.0.7 creates a fully privileged session before required multi-factor authentication enrollment is completed. An attacker with the password for an MFA-required but unenrolled account can access protected functionality without providing a second factor.
Which versions are affected by CVE-2026-84831?
How do I fix CVE-2026-84831?
No fix has been published for CVE-2026-84831 yet. Limit exposure of the affected software until one is available.
Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.
Is CVE-2026-84831 being exploited?
There is no known exploitation of CVE-2026-84831 in the wild and no public exploit code.
Sources
Also known as GHSA-4fw6-qxc4-gqgq.