CVE-2026-84831: CWE-287 - Improper Authentication in SEPPmail AG SEPPmail Secure Email Gateway (SEG)
Description
SEPPmail Secure Email Gateway versions before 15.0.7 have an improper authentication vulnerability where a fully privileged session is created before multi-factor authentication (MFA) enrollment is completed. This allows an attacker who knows the password of an MFA-required but unenrolled account to access protected functionality without providing the second factor.
CVSS v4.0
Score 7.7high
Affected software
SEPPmail AG
SEPPmail Secure Email Gateway (SEG)
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-84831 is an improper authentication vulnerability (CWE-287) in SEPPmail Secure Email Gateway (SEG) prior to version 15.0.7. The product creates a fully privileged session before the required MFA enrollment process is finalized. Consequently, an attacker possessing the password for an account that mandates MFA but has not completed enrollment can bypass the second authentication factor and gain access to protected features.
Potential Impact
An attacker with valid credentials for an MFA-required but unenrolled account can bypass the second factor and gain unauthorized access to privileged functionality within the SEPPmail Secure Email Gateway. This elevates the risk of unauthorized actions and potential compromise of sensitive email gateway operations.
Mitigation Recommendations
Upgrade SEPPmail Secure Email Gateway to version 15.0.7 or later, where this improper authentication issue has been addressed. No other mitigation or temporary workaround is indicated in the available data.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- NCSC.ch
- Date Reserved
- 2026-09-02T11:31:39.002Z
- Cvss Version
- 4.0
- State
- PUBLISHED
Threat ID: 6a9935a4acd9273b49b205a3
Added to database: 09/03/2026, 08:53:56 UTC
Last enriched: 10/09/2026, 21:29:56 UTC
Last updated: 10/17/2026, 18:48:23 UTC
Views: 77
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
External Links
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.