{"id":"CVE-1999-1306","title":"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.","summary":"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.","severity":"high","cvss":7.5,"cvssVector":"AV:N/AC:L/Au:N/C:P/I:P/A:P","published":"1992-12-10","updated":"2026-06-16","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-1999-1306","references":[{"url":"http://www.cert.org/advisories/CA-1992-20.html","label":"cve@mitre.org"},{"url":"http://www.cert.org/advisories/CA-1992-20.html","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.01394,"epssPercentile":0.70759,"ingestedAt":"2026-06-19T03:39:00.709Z","slug":"CVE-1999-1306","body":"## Overview\n\nCisco 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"twilight","depthScore":42,"depthScoreParts":{"impact":41.3,"likelihood":0.3,"exploitation":0,"ransomware":0},"changes":[]}