How severe is CVE-1999-1306?

CVE-1999-1306 has a CVSS 2.0 base score of 7.5, rated high severity.

Is CVE-1999-1306 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-1999-1306?

CVE-1999-1306 affects Cisco Ios. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-1999-1306?

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-1999-1306 published?

CVE-1999-1306 was published on 1992-12-10 and last updated on 2026-06-16.

CVE-1999-1306

CVE-1999-1306 is a high-severity vulnerability in Cisco Ios 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.

Key facts

Severity: High (CVSS 2.0 base score 7.5)
EPSS exploit prediction: 1% (69th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Cisco Ios
Published: 1992-12-10
Last modified: 2026-06-16

Description

Cisco IOS 9.1 and earlier does not properly handle extended IP access lists when the IP route cache is enabled and the "established" keyword is set, which could allow attackers to bypass filters.

Frequently asked questions

What is CVE-1999-1306?: Cisco IOS 9.1 and earlier does not properly handle extended IP access lists when the IP route cache is enabled and the "established" keyword is set, which could allow attackers to bypass filters.
How severe is CVE-1999-1306?: CVE-1999-1306 has a CVSS 2.0 base score of 7.5, rated high severity.
Is CVE-1999-1306 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (69th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-1999-1306?: CVE-1999-1306 affects Cisco Ios. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-1999-1306?: 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-1999-1306 published?: CVE-1999-1306 was published on 1992-12-10 and last updated on 2026-06-16.

References

http://www.cert.org/advisories/CA-1992-20.html

Affected products (1)

cpe:2.3:o:cisco:ios:*:*:*:*:*:*:*:*

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