How severe is CVE-1999-0775?

CVE-1999-0775 has a CVSS 2.0 base score of 10.0, rated critical severity.

Is CVE-1999-0775 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-1999-0775?

CVE-1999-0775 primarily affects Cisco Ios. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-1999-0775?

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

When was CVE-1999-0775 published?

CVE-1999-0775 was published on 1999-06-10 and last updated on 2026-06-16.

CVE-1999-0775

CVE-1999-0775 is a critical-severity vulnerability in Cisco Ios with a CVSS 2.0 base score of 10.0. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.

Key facts

Severity: Critical (CVSS 2.0 base score 10.0)
EPSS exploit prediction: 3% (86th percentile)
Actively exploited: Not listed in CISA KEV
Affected product: Cisco Ios
Published: 1999-06-10
Last modified: 2026-06-16

Description

Cisco Gigabit Switch routers running IOS allow remote attackers to forward unauthorized packets due to improper handling of the "established" keyword in an access list.

Frequently asked questions

What is CVE-1999-0775?: Cisco Gigabit Switch routers running IOS allow remote attackers to forward unauthorized packets due to improper handling of the "established" keyword in an access list.
How severe is CVE-1999-0775?: CVE-1999-0775 has a CVSS 2.0 base score of 10.0, rated critical severity.
Is CVE-1999-0775 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (86th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-1999-0775?: CVE-1999-0775 primarily affects Cisco Ios. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-1999-0775?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-1999-0775 published?: CVE-1999-0775 was published on 1999-06-10 and last updated on 2026-06-16.

References

https://exchange.xforce.ibmcloud.com/vulnerabilities/CVE-1999-0775

Affected products (2)

cpe:2.3:o:cisco:ios:11.2\(14\)gs2:*:*:*:*:*:*:*
cpe:2.3:o:cisco:ios:11.2\(15\)g:*:*:*:*:*:*:*

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