CVE-2026-27444Network attack vector

Unauthenticated email spoofing via conflicting address parsing

Published Mar 4, 2026 · Updated Mar 4, 2026

Interpretation conflict in SEPPmail Secure Email Gateway before 15.0.1 allows remote attackers to spoof email sources or decrypt mail. The gateway parses addresses in message headers differently from other mail infrastructure, assigning conflicting sender or recipient identities to crafted syntax. No authentication or user interaction is required; the bounded effects are forged message origin and unauthorized plaintext recovery.

CVSS severity7.8
High
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Interpretation conflict in SEPPmail Secure Email Gateway before 15.0.1 allows remote attackers to spoof email sources or decrypt mail. The gateway parses addresses in message headers differently from other mail infrastructure, assigning conflicting sender or recipient identities to crafted syntax. No authentication or user interaction is required; the bounded effects are forged message origin and unauthorized plaintext recovery.

The record

CVE
CVE-2026-27444
Published
Mar 4, 2026
Updated
Mar 4, 2026
Vendor
SEPPmail
Product
Secure Email Gateway
Classifications
CWE-436, CAPEC-194, T1036
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 4, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <15.0.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

SEPPmail · Secure Email Gatewayversion=0 <15.0.1

Published CVSS scores

7.5NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
7.8Switzerland Government Common Vulnerability ProgramCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:H/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-436Interpretation Conflict
CAPEC-194Fake the Source of Data
T1036Masquerading

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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