Description

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.

Classification

CVE ID: CVE-2025-34491

CVSS Base Severity: HIGH

CVSS Base Score: 8.8

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Products

Vendor: GFI

Product: MailEssentials

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.09% (probability of being exploited)

EPSS Percentile: 26.09% (scored less or equal to compared to others)

EPSS Date: 2025-05-27 (when was this score calculated)

Stakeholder-Specific Vulnerability Categorization (SSVC)

SSVC Exploitation: poc

SSVC Technical Impact: total

SSVC Automatable: false

References

https://nvd.nist.gov/vuln/detail/CVE-2025-34491
https://frycos.github.io/vulns4free/2025/04/28/mailessentials.html
https://gfi.ai/products-and-solutions/network-security-solutions/mailessentials/resources/documentation/product-releases

Timeline