Deserialization in Gfi Mailessentials
CVE-2025-34491
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.
Vulnerability class: Insecure Deserialization
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.010 (61.6th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 62nd percentile — 61.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.010 · change: +0.000
Affected products
- Gfi Mailessentials — versions 0
Weakness classification (CWE)
References
- frycos.github.io/vulns4free/2025/04/28/mailessentials.html (Exploit, technical-description, exploit)
- gfi.ai/products-and-solutions/network-security-solutions/mailessentials/resourc… (vendor-advisory, Release Notes)
- www.vulncheck.com/advisories/gfi-mailessentials-multinode-insecure-deserializat… (third-party-advisory)
Frequently asked questions
- What is CVE-2025-34491?
- CVE-2025-34491 is a high-severity vulnerability in Gfi Mailessentials, classified under Deserialization of Untrusted Data. CVSS score: 8.8/10. Published 2025-04-28.
- How severe is CVE-2025-34491?
- High severity. CVSS v3 base score is 8.8 out of 10.