CVE-2018-15454: Cisco Adaptive Security Appliance Software and Cisco Firepower Threat Defense Software Denial of Service Vulnerability

Severity: high (CVSS 8.6 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 4.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2018-11-01 · updated 2026-08-11
Weakness: CWE-20

Description

A vulnerability in the Session Initiation Protocol (SIP) inspection engine of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause an affected device to reload or trigger high CPU, resulting in a denial of service (DoS) condition. The vulnerability is due to improper handling of SIP traffic. An attacker could exploit this vulnerability by sending SIP requests designed to specifically trigger this issue at a high rate across an affected device. Software updates that address this vulnerability are not yet available.

Affected products

Cisco ASA Software: from 9.4 before 9.4.4.27; from 9.6 before 9.6.4.18; from 9.8 before 9.8.3.16; from 9.9 before 9.9.2.32; from 9.10 before 9.10.1.2 — fixed in 9.10.1.2, 9.4.4.27, 9.6.4.18, 9.8.3.16, 9.9.2.32
Cisco Firepower Threat Defense Software: from 6.1.0 before 6.1.0.7; from 6.2.0 before 6.2.0.6; from 6.2.2 before 6.2.2.4; from 6.2.3 before 6.2.3.7 — fixed in 6.1.0.7, 6.2.0.6, 6.2.2.4, 6.2.3.7

How to fix

Upgrade to a fixed version: Cisco ASA Software 9.10.1.2, 9.4.4.27, 9.6.4.18, 9.8.3.16; Cisco Firepower Threat Defense Software 6.1.0.7, 6.2.0.6, 6.2.2.4, 6.2.3.7. Check the vendor advisory for mitigations.

References

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