Description
A vulnerability in the Session Initiation Protocol (SIP) inspection module of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device. The vulnerability is due to improper parsing of SIP messages. An attacker could exploit this vulnerability by sending a malicious SIP packet through an affected device. A successful exploit could allow the attacker to trigger an integer underflow, causing the software to try to read unmapped memory and resulting in a crash.
Affected products
cisco: adaptive security appliance; cisco: adaptive security appliance software; cisco: asa 5505; cisco: asa 5510; cisco: asa 5512-x; cisco: asa 5515-x; cisco: asa 5520; cisco: asa 5525-x; cisco: asa 5550; cisco: asa 5555-x; cisco: asa 5580; cisco: asa 5585-x; cisco: secure firewall threat defense
References2
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/c… Vendor Advisory
- tools.cisco.com/security/center/content/CiscoSecurityAdvisory/c… Vendor Advisory
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: NVD
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 2% percentile: 79 · as of 10 November 2026
- CWE
- CWE-191
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.