CVE-2007-4321

fail2ban 0.8 and earlier does not properly parse sshd log files, which allows remote attackers to add arbitrary hosts to the /etc/hosts.deny file and cause a denial of service by adding arbitrary IP addresses to the sshd log file, as demonstrated by logging in via ssh with a client protocol version identification containing an IP address string, a different vector than CVE-2006-6302.

CVE ID:

CVE-2007-4321

Published:

2007-08-14

Modified:

2026-04-23

CVSS Score:

6.8

Severity:

MEDIUM

Vector:

AV:N/AC:M/Au:N/C:P/I:P/A:P