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 "

Published n/a Updated 2026-08-21T04:30:36.303Z

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

UNKNOWN

Source Attribution

Source: NVD · Updated: 2026-08-21T04:30:36.303Z · Confidence: high

Impact

Based on CVSS vector: n/a — assess confidentiality, integrity, and availability impact via the official vector documentation.

Affected Software

Fix

Upgrade affected software to the fixed version identified above. Apply vendor patches and monitor advisories before exposed systems go unpatched.

References