CVE-2009-1168: Cisco IOS

High severity, CVSS 7.1. EPSS: 2.5% chance of exploitation in the next 30 days.

Cisco IOS 12.0(32)S12 through 12.0(32)S13 and 12.0(33)S3 through 12.0(33)S4, 12.0(32)SY8 through 12.0(32)SY9, 12.2(33)SXI1, 12.2XNC before 12.2(33)XNC2, 12.2XND before 12.2(33)XND1, and 12.4(24)T1; and IOS XE 2.3 through 2.3.1t and 2.4 through 2.4.0; when RFC4893 BGP routing is enabled, allows remote attackers to cause a denial of service (memory corruption and device reload) by using an RFC4271 peer to send an update with a long series of AS numbers, aka Bug ID CSCsy86021.

Affected products

• Cisco IOS: version 12.0(32)s12 only; version 12.0(32)s13 only; version 12.0(32)sy8 only; version 12.0(32)sy9 only; version 12.0(33)s3 only; version 12.0(33)s4 only; …
• Cisco IOS XE: version 2.3 only; version 2.3.1t only; version 2.4 only; version 2.4.0 only

Published 2009-07-30. Last modified 2026-06-16.