CVE-2026-27444 Header Email Address Parsing

What is CVE-2026-27444?

CVE-2026-27444 is a high-severity vulnerability in SEPPmail Secure Email Gateway, published on 4 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

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.

Weakness: CWE-436

Which versions are affected by CVE-2026-27444?

It affects 1 product.

Products include Seppmail Seppmail.

How do I fix CVE-2026-27444?

No fix has been published for CVE-2026-27444 yet. Limit exposure of the affected software until one is available.

Is CVE-2026-27444 being exploited?

There is no known exploitation of CVE-2026-27444 in the wild and no public exploit code.

Other vulnerabilities in SEPPmail Secure Email Gateway

• CVE-2026-2743 SEPPmail User Web Interface Arbitrary File Write to RCE Critical 10.0
• CVE-2026-27441 PDF Password CMDi Critical 9.5
• CVE-2026-27442 zip_attachments Path Traversal Critical 9.3
• CVE-2026-27443 S/MIME Decryption Tag Sanitization Bypass High 8.2
• CVE-2026-2748 S/MIME Certificate Subject Whitespace High 7.8

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-5wwg-q432-32vv.