CVE-2025-34491: GFI MailEssentials · Deserialization of Untrusted Data
Affects GFI MailEssentialsSource GCVE Database
Not known to be exploited · CVSS 8.8 High : upgrade to 21.8 soon.
Data as of 13 Nov 2026, 20:18 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 3.1 | 8.8 |
|---|
- Patch
- Available – fixed in 21.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 28 Apr 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Upgrade GFI MailEssentials to 21.8.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| GFI MailEssentials | Affected
| Fixed in
|
AI-suggested
Upgrade GFI MailEssentials to version 21.8 or later, where this vulnerability is fixed. No other mitigation or workaround is indicated in the available data.
Description
GFI MailEssentials versions prior to 21.8 contain a deserialization vulnerability in their .NET implementation. This flaw allows a remote authenticated attacker to execute arbitrary code by sending crafted serialized .NET data when joining a Multi-Server setup. The vulnerability is rated high severity with a CVSS score of 8.8.
References
- frycos.github.io/vulns4free/2025/04/28/mailessentials.html (opens in a new tab)
- gfi.ai/products-and-solutions/network-security-solutions/mailessentials/resources/documentation/product-releases (opens in a new tab)
- vulncheck.com/advisories/gfi-mailessentials-multinode-insecure-deserialization (opens in a new tab)