CVE-2025-34489Public exploit

SYSTEM code execution via unsafe remoting deserialization

Published Apr 28, 2025 · Updated Nov 19, 2025

Deserialization in GFI MailEssentials before 21.8 allows local users to execute code as NT AUTHORITY\SYSTEM through a crafted remoting payload. Its localhost TCP .NET Remoting services use BinaryFormatter to deserialize attacker-controlled objects without restricting permitted types. A low-privilege Windows account on the MailEssentials server is required, and successful exploitation grants full SYSTEM control.

CVSS severity7.8
High
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Deserialization in GFI MailEssentials before 21.8 allows local users to execute code as NT AUTHORITY\SYSTEM through a crafted remoting payload. Its localhost TCP .NET Remoting services use BinaryFormatter to deserialize attacker-controlled objects without restricting permitted types. A low-privilege Windows account on the MailEssentials server is required, and successful exploitation grants full SYSTEM control.

The record

CVE
CVE-2025-34489
Published
Apr 28, 2025
Updated
Nov 19, 2025
Vendor
GFI Software
Product
GFI MailEssentials
Classifications
CWE-502, CAPEC-586, CAPEC-233, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 28, 2025CVE publishedPublication date reported by the CVE source.
  2. Nov 19, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <21.8

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

GFI Software · GFI MailEssentialsversion=0 <21.8

Published CVSS scores

7.8VulnCheckCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-502Deserialization of Untrusted Data
CAPEC-586Object Injection
CAPEC-233Privilege Escalation
T1068Exploitation for Privilege Escalation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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