THREATPORT/VULNERABILITY/CVE-2007-4321
MEDIUM SEVERITY

CVE-2007-4321

Fail2ban vulnerability

CVSS
6.8
EPSS
5.7%
EPSS pct
92th
Exploited
No known
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.
Affected vendor
Fail2ban
Affected product
Fail2ban
CVSS vector
AV:N/AC:M/Au:N/C:P/I:P/A:P
Published
2007-08-14

Risk analysis

Based on its CVSS vector, this vulnerability is exploitable over the network, medium attack complexity, requiring no authentication. Successful exploitation leads to partial impact to confidentiality, partial impact to integrity, partial impact to availability.

Its EPSS score of 5.7% reflects a lower probability of exploitation activity in the wild over the next 30 days, placing it above 92% of all scored CVEs.

Check your external exposure to CVE-2007-4321

  • Confirm whether Fail2ban Fail2ban is running on any internet-facing host or subdomain.
  • Match discovered service fingerprints against the version affected by CVE-2007-4321.
  • Prioritise remediation if the asset is public, business-critical, or near authentication/payment flows.

How ThreatPort helps with CVE-2007-4321

ThreatPort's external attack surface scanner checks your internet-facing assets — agentlessly, from the outside in — for the exposed services and versions that CVE-2007-4321 affects, then prioritises the finding by real risk using CISA KEV and FIRST.org EPSS.

Run a free external exposure scan

Are you exposed to CVE-2007-4321?

Run an instant, non-intrusive external scan to check your attack surface for CVE-2007-4321.

Start free scan

No credit card. Agentless.

Related vulnerabilities

MEDIUM
CVE-2025-5763
Cp3 Firmware vulnerability
MEDIUM
CVE-2025-5301
CVE-2025-5301 vulnerability
MEDIUM
CVE-2025-5964
M Files Server vulnerability