CVE-2026-2748

S/MIME Certificate Subject Whitespace

7.8 High

CVE-2026-2748 is a high vulnerability (CVSS 7.8) in Seppmail Secure Email Gateway, published March 4, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.13%, the 2nd percentile. No source names a fixed version.

What does this mean?

Severity: 7.8 HighCVSS 4.0, CVE List
Exploit chance: 0.13%EPSS, 2nd percentile
Exploitation: None knownNot on CISA’s or ENISA’s lists
Fixed in: No fix listedNo source names one

Description

SEPPmail Secure Email Gateway before version 15.0.1 improperly validates S/MIME certificates issued for email addresses containing whitespaces, allowing signature spoofing.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: None

What an attacker can affect

Confidentiality: None
Integrity: Low
Availability: None

Exploit likelihood

0.13%Up 0.1 points since Mar 4, 2026

Affected products

What each source reports

CVE List Score used7.8

S/MIME Certificate Subject Whitespace

SEPPmail Secure Email Gateway before version 15.0.1 improperly validates S/MIME certificates issued for email addresses containing whitespaces, allowing signature spoofing.

Record: CVE-2026-2748
CVSS 4.0: 7.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:H/SA:N
Weakness: CWE-295
Updated: 2026-11-02

EUVDEUVD-2026-93857.8

SEPPmail Secure Email Gateway before version 15.0.1 improperly validates S/MIME certificates issued for email addresses containing whitespaces, allowing signature spoofing.

Record: EUVD-2026-9385
CVSS 4.0: 7.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:H/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-qg5v-hxpj-p53x7.8

SEPPmail Secure Email Gateway before version 15.0.1 improperly validates S/MIME certificates...

SEPPmail Secure Email Gateway before version 15.0.1 improperly validates S/MIME certificates issued for email addresses containing whitespaces, allowing signature spoofing.

Record: GHSA-qg5v-hxpj-p53x
CVSS 4.0: 7.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness: CWE-295
Updated: 2026-11-02

NVD7.8

SEPPmail Secure Email Gateway before version 15.0.1 improperly validates S/MIME certificates issued for email addresses containing whitespaces, allowing signature spoofing.

Record: CVE-2026-2748
CVSS 4.0: 7.8 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:L/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
Weakness: CWE-295
Updated: 2026-11-02

History

History
Recorded	Changed	Sources
Nov 2, 2026	first indexed	CVE List, EUVD, GitHub Advisories, NVD

Dates are when Every CVE recorded each change. Upstream dates may differ.

Description

Attack profile

How easy it is to exploit

What an attacker can affect

Exploit likelihood

Affected products

What each source reports

History

References