CVE-2007-4321

Exp

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.

Published: 2007-08-14 Last update: 2026-04-23 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2007-4321 is rated High Exploit Risk (69.4/100): CVSS Medium severity, with high exploitation likelihood (EPSS 5.75%, 92th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2007-4321

EDB-ID Source Kind Published Link
30430 exploit_db edb 2007-07-28 Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2007-4321

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 12.11% 5.75% -6.36%
2 2026-04-02 11.70% 12.11% +0.41%
3 2025-10-29 — 11.70% —

Full EPSS history (15 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2007-4321

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2007-4321

OS Trackers for CVE-2007-4321

vendor priority summary link
debian medium CVE-2007-4321 medium priority: Debian including 1 source packages (fail2ban), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2007-4321
gentoo normal CVE-2007-4321: 1 GLSA(s) (200707-13), 1 atom(s) (net-analyzer/fail2ban); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2007-4321
ubuntu medium CVE-2007-4321 medium priority: Ubuntu including 1 source packages (fail2ban), 9 status rows across 9 suites (dapper, edgy, feisty, gutsy, hardy, intrepid, jaunty, karmic, upstream): released 5, ignored 3, needs-triage 1. https://ubuntu.com/security/CVE-2007-4321

Affected software / configurations for CVE-2007-4321

Vendor Product Version Raw CPE
fail2ban fail2ban 0.8 cpe:2.3:a:fail2ban:fail2ban:0.8:*:*:*:*:*:*:*

References for CVE-2007-4321

cvelogic Threat Intelligence