Is CVE-1999-1109 actively exploited?

A proof-of-concept exploit is publicly available for CVE-1999-1109, but active exploitation has not been confirmed.

Can CVE-1999-1109 be exploited remotely?

Yes. CVE-1999-1109 is exploitable remotely over the network (CVSS attack vector: Network).

What is the CVSS score of CVE-1999-1109?

CVE-1999-1109 has a CVSS score of 5.0 (MEDIUM).

HOME VULNERABILITIESCVE-1999-1109

MEDIUMPOC

CVE-1999-1109

NVD-CWE-OtherPublished: December 22, 1999· Updated: Jun 16, 2026

5.0

CVSS v3.1

Official Description

Sendmail before 8.10.0 allows remote attackers to cause a denial of service by sending a series of ETRN commands then disconnecting from the server, while Sendmail continues to process the commands after the connection has been terminated.

NVD Source

Technical Analysis

CVE-1999-1109 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.

A proof-of-concept (PoC) exploit exists for CVE-1999-1109. While not yet confirmed in active campaigns, the availability of PoC code increases exploitation risk substantially.