CVE-2025-34491

GFI MailEssentials < 21.8 MultiNode Insecure Deserialization

8.8 High

GFI MailEssentials prior to version 21.8 is vulnerable to a .NET deserialization issue. A remote and authenticated attacker can execute arbitrary code by sending crafted serialized .NET when joining to a Multi-Server setup.

Attack profile

How easy it is to exploit

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

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

0.96%Up 0.9 points since Apr 29, 2025

What each source reports

CVE List Score used 8.8

GFI MailEssentials < 21.8 MultiNode Insecure Deserialization

Record: CVE-2025-34491
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-502
Updated: 2026-11-02

EUVDEUVD-2025-14683 8.8

Record: EUVD-2025-14683
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Updated: 2026-11-02

GitHub AdvisoriesGHSA-fqqj-qgxm-vg3x 8.8

GFI MailEssentials prior to version 21.8 is vulnerable to a .NET deserialization issue. A remote...

Record: GHSA-fqqj-qgxm-vg3x
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-502
Updated: 2026-11-02

NVD 8.8

Record: CVE-2025-34491
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Weakness: CWE-502
Updated: 2026-11-02

Affected products

gfi mailessentials

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.

In short

CVE-2025-34491 is a high vulnerability (CVSS 8.8) in Gfi Mailessentials, published April 28, 2025. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.96%, the 61st percentile. No source names a fixed version.