How severe is CVE-1999-0063?

CVE-1999-0063 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-1999-0063 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 8% (94th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-1999-0063?

CVE-1999-0063 primarily affects Cisco Ios. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-1999-0063?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-1999-0063 published?

CVE-1999-0063 was published on 1999-01-11 and last updated on 2026-06-16.

CVE-1999-0063

CVE-1999-0063 is a medium-severity vulnerability in Cisco Ios with a CVSS 2.0 base score of 5.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 8% (94th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Cisco Ios
Published: 1999-01-11
Last modified: 2026-06-16

Description

Cisco IOS 12.0 and other versions can be crashed by malicious UDP packets to the syslog port.

Frequently asked questions

What is CVE-1999-0063?: Cisco IOS 12.0 and other versions can be crashed by malicious UDP packets to the syslog port.
How severe is CVE-1999-0063?: CVE-1999-0063 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-1999-0063 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 8% (94th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-1999-0063?: CVE-1999-0063 primarily affects Cisco Ios. In total, 12 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-1999-0063?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-1999-0063 published?: CVE-1999-0063 was published on 1999-01-11 and last updated on 2026-06-16.

References

https://exchange.xforce.ibmcloud.com/vulnerabilities/CVE-1999-0063

Affected products (12)

cpe:2.3:o:cisco:ios:11.3aa:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:11.3db:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)w:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)xa3:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)xb:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(1\)xe:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xc:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0\(2\)xd:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0db:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0s:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:12.0t:*:*:*:*:*:*:*

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