How to Fix CVE-2026-2748: Secure Email Gateway (Bundle Sibling)
By Sai Kiran Pandrala. Last verified: 2026-05-25.
CVE-2026-2748 is a sibling vulnerability in the same vendor advisory as CVE-2026-27441. Apply the same patched build and you close both. The technical detail below is what differs.
| Severity | 7.8 (High) |
|---|---|
| Actively exploited? | No public listing in CISA KEV |
| Affected | Secure Email Gateway 0 to <15.0.1 |
| Fixed in | Same patched build as CVE-2026-27441 |
| Type (CWE) | CWE-295 Improper Certificate Validation |
What's different about CVE-2026-2748?
SEPPmail Secure Email Gateway before version 15.0.1 improperly validates S/MIME certificates issued for email addresses containing whitespaces, allowing signature spoofing.
How to fix CVE-2026-2748
Apply the patched build per the primary write-up: How to Fix CVE-2026-27441. All commands, verification steps, and rollback notes for Secure Email Gateway are listed there.
Frequently asked questions
Does the CVE-2026-27441 patch close CVE-2026-2748?
Yes. Both CVEs are addressed by the same vendor patch. Applying the patched build closes the full bundle.
Is CVE-2026-2748 listed in CISA KEV?
No public KEV listing at the time of this writing.
Where is the official advisory?
See https://downloads.seppmail.com/extrelnotes/150/ERN15.0.html#seppmail-vulnerability-disclosure
References
- Official vendor advisory: https://downloads.seppmail.com/extrelnotes/150/ERN15.0.html#seppmail-vulnerability-disclosure
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-2748
- CISA KEV catalog: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- Primary: How to Fix CVE-2026-27441
*Written by Sai Kiran Pandrala. Part of the Secure Email Gateway bundle. Full procedure at how-to-fix-cve-2026-27441.*