CVE-2025-34491: gfi mailessentials Deserialization of Untrusted Data
CVSS: 8.8v3.1HighModified
Published 28-04-2025Last modified 19-11-2025
Vulnerability summary
CVE-2025-34491 is a high (CVSS 8.8) Deserialization of Untrusted Data vulnerability in gfi mailessentials. EPSS estimates a 0.95% chance of exploitation in the next 30 days, higher than 60.5% of scored vulnerabilities. 1 public exploit is recorded.
CVSS score
8.8/10
010
High · v3.1 (CVE.org)EPSS score
0.95%
0%100%
Low · +0.06 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1reference
Timeline
- 28-04-2025PublishedVulnerability first disclosed.
- 19-11-2025Last modifiedVulnerability information updated.
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.
CVSS metrics
2 scores · 2 sources · 1 versionHigh 8.8Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HSourcesAll 2 agree
- NVDNIST8.8HighCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.95%
Chance of exploitation in the next 30 days
Percentile
61%
Versus all other CVEs
30-day change
+0.06 pp
From 0.88% on 20-09-2026
20-09-202620-10-2026
EPSS score0.95%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
1 foundExploit Reference (frycos.github.io)
Maturity: unknown
Weaknesses
CWE · root causeAffected systems
Gfi1 product
- mailessentials< 21.8
1 vendor · 1 product