CVE-2012-3949: Cisco IOS

High severity, CVSS 7.8. EPSS: 3.2% chance of exploitation in the next 30 days.

The SIP implementation in Cisco Unified Communications Manager (CUCM) 6.x and 7.x before 7.1(5b)su5, 8.x before 8.5(1)su4, and 8.6 before 8.6(2a)su1; Cisco IOS 12.2 through 12.4 and 15.0 through 15.2; and Cisco IOS XE 3.3.xSG before 3.3.1SG, 3.4.xS, and 3.5.xS allows remote attackers to cause a denial of service (service crash or device reload) via a crafted SIP message containing an SDP session description, aka Bug IDs CSCtw66721, CSCtj33003, and CSCtw84664.

Affected products

• Cisco IOS: version 12.2 only; version 12.2b only; version 12.2bc only; version 12.2bw only; version 12.2bx only; version 12.2by only; …
• Cisco IOS XE: version 3.3.0sg only; version 3.3.1s only; version 3.3.1sg only; version 3.4.0as only; version 3.4.0s only; version 3.4.1s only; …
• Cisco Unified Communications Manager: version 6.0(1a) only; version 6.0(1b) only; version 6.1(1) only; version 6.1(1a) only; version 6.1(1b) only; version 6.1(2) only; …

Published 2012-09-27. Last modified 2026-06-16.