Skip to content
brandefense.io
Request A Demo
Vulnerability Intelligence

CVE-1999-0661

CriticalPublic exploit

A system is running a version of software that was replaced with a Trojan Horse at one of its distribution points, such as (1) TCP Wrappers 7.6, (2) util-linux 2.9g, (3) wuarchive ftpd (wuftpd) 2.2 and 2.1f, (4) IRC client (ircII) ircII 2.2.9, (5) OpenSSH 3.4p1, or (6) Sendmail…

Published Jan 1, 1999 · Updated Apr 15, 2026

Key Facts

Patch immediately
  • CVE-1999-0661 is a critical-severity vulnerability (CVSS 10.0 v2).
  • It is not listed in any known-exploited vulnerabilities catalog. Public exploit code is available.
  • EPSS estimates a 54% probability of exploitation in the next 30 days.
  • No fixed version is listed yet; check the vendor advisory for mitigations.
  • Brandefense priority: patch immediately, because it is very likely to be exploited soon.

CVSS v2

10.0

AV:N/AC:L/Au:N/C:C/I:C/A:C

EPSS (30-day exploit likelihood)

54%

Higher than 99.0% of all scored CVEs

Exploited in the wild

No known

Not in a known-exploited catalog

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-1999-0661 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

A system is running a version of software that was replaced with a Trojan Horse at one of its distribution points, such as (1) TCP Wrappers 7.6, (2) util-linux 2.9g, (3) wuarchive ftpd (wuftpd) 2.2 and 2.1f, (4) IRC client (ircII) ircII 2.2.9, (5) OpenSSH 3.4p1, or (6) Sendmail 8.12.6.

Timeline

  1. Publicly disclosed

    Jan 1, 1999

  2. Last updated

    Apr 15, 2026

References

6 more references in the full CVE brief

FAQ

Common Questions.

Is CVE-1999-0661 Running On Your Attack Surface?

Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.

Request A Demo