CVE-2011-4597: Digium Asterisk

Medium severity, CVSS 5.0. EPSS: 3.2% chance of exploitation in the next 30 days.

The SIP over UDP implementation in Asterisk Open Source 1.4.x before 1.4.43, 1.6.x before 1.6.2.21, and 1.8.x before 1.8.7.2 uses different port numbers for responses to invalid requests depending on whether a SIP username exists, which allows remote attackers to enumerate usernames via a series of requests.

Affected products

• Digium Asterisk: version 1.8.0 only; version 1.8.1 only; version 1.8.1.1 only; version 1.8.1.2 only; version 1.8.2 only; version 1.8.2.1 only; …

Published 2011-12-15. Last modified 2026-06-16.