SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-27444

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.

HIGH 7.8EPSS 0.21%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (0.21%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

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.

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/M
EPSS
0.21% probability · 12th percentile
CISA KEV
Not listed
Weakness
CWE-436
Affected
seppmail/seppmail
Source
vulnerability@ncsc.ch

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.