How severe is CVE-2003-1491?

CVE-2003-1491 has a CVSS 2.0 base score of 7.5, rated high severity.

Is CVE-2003-1491 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2003-1491?

CVE-2003-1491 affects Kerio Personal Firewall. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2003-1491?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2003-1491 published?

CVE-2003-1491 was published on 2003-12-31 and last updated on 2026-06-16.

CVE-2003-1491

CVE-2003-1491 is a high-severity vulnerability in Kerio Personal Firewall with a CVSS 2.0 base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-16.

Key facts

Severity: High (CVSS 2.0 base score 7.5)
EPSS exploit prediction: 2% (82nd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-16
Affected product: Kerio Personal Firewall
Published: 2003-12-31
Last modified: 2026-06-16

Description

Kerio Personal Firewall (KPF) 2.1.4 has a default rule to accept incoming packets from DNS (UDP port 53), which allows remote attackers to bypass the firewall filters via packets with a source port of 53.

Frequently asked questions

What is CVE-2003-1491?: Kerio Personal Firewall (KPF) 2.1.4 has a default rule to accept incoming packets from DNS (UDP port 53), which allows remote attackers to bypass the firewall filters via packets with a source port of 53.
How severe is CVE-2003-1491?: CVE-2003-1491 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-2003-1491 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (82nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2003-1491?: CVE-2003-1491 affects Kerio Personal Firewall. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2003-1491?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2003-1491 published?: CVE-2003-1491 was published on 2003-12-31 and last updated on 2026-06-16.

References

Affected products (1)

cpe:2.3:a:kerio:personal_firewall:2.1.4:*:*:*:*:*:*:*

More vulnerabilities in Kerio Personal Firewall

CVE-2005-1062 — High (CVSS 7.5): The administration protocol for Kerio WinRoute Firewall 6.x up to 6.0.10, Personal Firewall 4.x up to 4.1.2, and…
CVE-2004-2329 — High (CVSS 7.2): Kerio Personal Firewall (KPF) 2.1.5 allows local users to execute arbitrary code with SYSTEM privileges via the Load…
CVE-2006-5153 — Medium (CVSS 5.0): The (1) fwdrv.sys and (2) khips.sys drivers in Sunbelt Kerio Personal Firewall 4.3.268 and earlier do not validate…
CVE-2005-1063 — Medium (CVSS 5.0): The administration protocol for Kerio WinRoute Firewall 6.x up to 6.0.10, Personal Firewall 4.x up to 4.1.2, and…
CVE-2004-1109 — Medium (CVSS 5.0): The FWDRV.SYS driver in Kerio Personal Firewall 4.1.1 and earlier allows remote attackers to cause a denial of service…
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