How severe is CVE-2026-27443?

CVE-2026-27443 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.

Is CVE-2026-27443 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-27443?

CVE-2026-27443 affects Seppmail. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-27443?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2026-27443 have an EU (EUVD) identifier?

Yes. CVE-2026-27443 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9379.

When was CVE-2026-27443 published?

CVE-2026-27443 was published on 2026-03-04 and last updated on 2026-06-17.

CVE-2026-27443

CVE-2026-27443 is a high-severity vulnerability in Seppmail with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 8.2
EPSS exploit prediction: 0% (12th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-9379
Weakness: CWE-20
Affected product: Seppmail
Published: 2026-03-04
Last modified: 2026-06-17

Description

SEPPmail Secure Email Gateway before version 15.0.1 does not properly sanitize the headers from S/MIME protected MIME entities, allowing an attacker to control trusted headers.

Frequently asked questions

What is CVE-2026-27443?: SEPPmail Secure Email Gateway before version 15.0.1 does not properly sanitize the headers from S/MIME protected MIME entities, allowing an attacker to control trusted headers.
How severe is CVE-2026-27443?: CVE-2026-27443 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
Is CVE-2026-27443 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (12th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-27443?: CVE-2026-27443 affects Seppmail. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-27443?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2026-27443 have an EU (EUVD) identifier?: Yes. CVE-2026-27443 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-9379.
When was CVE-2026-27443 published?: CVE-2026-27443 was published on 2026-03-04 and last updated on 2026-06-17.

References

https://downloads.seppmail.com/extrelnotes/150/ERN15.0.html#seppmail-vulnerability-disclosure

Affected products (1)

cpe:2.3:a:seppmail:seppmail:*:*:*:*:*:*:*:*

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