CVE-1999-1129: Cisco Catalyst 2900 Virtual LAN (VLAN) switches allow remote attackers to inject 802.1q frames into another VLAN by forg

Published n/a Updated 2026-08-21T04:30:49.120Z

Summary

Cisco Catalyst 2900 Virtual LAN (VLAN) switches allow remote attackers to inject 802.1q frames into another VLAN by forging the VLAN identifier in the trunking tag.

Severity

UNKNOWN

Source Attribution

Source: NVD · Updated: 2026-08-21T04:30:49.120Z · 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