Secure Email Gateway: Interpretation Conflict
CVE-2026-27444 is a high-severity interpretation conflict vulnerability in Secure Email Gateway from SeppMail, with a CVSS 3.1 base score of 7.5 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. The record lists version 15.0.1 as the first without the flaw, so updating Secure Email Gateway to that release or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.25% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Secure Email Gateway to 15.0.1 or a later version.
- Update Seppmail to 15.0.1 or a later version.
- Read the advisory on downloads.seppmail.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| SEPPmail | Secure Email Gateway | before 15.0.1 | 15.0.1 |
| Seppmail | Seppmail | before 15.0.1 | 15.0.1 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- NoneNo data is disclosed.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 7.8 | High | CNA (ncsc.ch) |
| CVSS 3.1 | 7.5 | High | NVD |
Official description
SEPPmail Secure Email Gateway before version 15.0.1 incorrectly interprets email addresses in the email headers, causing an interpretation conflict with other mail infrastructure that allows an attacker to fake the source of the email or decrypt it.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Interpretation Conflict
Product A handles inputs or steps differently than Product B, which causes A to perform incorrect actions based on its perception of B's state.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Other vulnerabilities in Secure Email Gateway
- 8.6 High severity
- 7.1 High severity
- 8.3 High severity
- 9.3 Critical severity
- 8.8 High severity
- 9.2 Critical severity
Recent Interpretation Conflict vulnerabilities
- 7.5 High severity
- 7.5 High severity
- 8.6 High severity
- 7.5 High severity
- 7.5 High severity
- 9.1 Critical severity
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