CVE-2026-84831 PUBLISHED

Mandatory MFA bypass before enrollment

Assigner: NCSC.ch
Reserved: 02.09.2026 Published: 03.09.2026 Updated: 03.09.2026

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.

Metrics

CVSS 4.0

CVSS Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
CVSS Score: 7.7

Exploitability Metrics		Vulnerable System Impact Metrics		Subsequent System Impact Metrics
Attack Vector	Network	Confidentiality	High	Confidentiality	None
Attack Complexity	Low	Integrity	High	Integrity	None
Attack Requirements	Present	Availability	High	Availability	None
Privileges Required	Low
User Interaction	None

CVSS 4.0

Product Status

Vendor	SEPPmail AG
Product	SEPPmail Secure Email Gateway (SEG)
Versions	Default: unaffected affected from 0 to 15.0.7 (excl.)

Credits

Emposo GmbH finder

References

https://downloads.seppmail.com/extrelnotes/150/ERN15.0.html

Problem Types

CWE-287 - Improper Authentication CWE
CWE-306 Missing authentication for critical function CWE

Impacts

CAPEC-115 Authentication Bypass