Cisco UTD Snort IPS Engine Software for Cisco IOS XE Software Security Policy Bypass and Denial of Service Vulnerability

published 2024-09-25 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-18223

cvss: 5.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 36%
public exploits: 0; none known

A vulnerability in Cisco Unified Threat Defense (UTD) Snort Intrusion Prevention System (IPS) Engine for Cisco IOS XE Software could allow an unauthenticated, remote attacker to bypass configured security policies or cause a denial of service (DoS) condition on an affected device.

This vulnerability is due to insufficient validation of HTTP requests when they are processed by Cisco UTD Snort IPS Engine. An attacker could exploit this vulnerability by sending a crafted HTTP request through an affected device. A successful exploit could allow the attacker to trigger a reload of the Snort process. If the action in case of Cisco UTD Snort IPS Engine failure is set to the default, fail-open, successful exploitation of this vulnerability could allow the attacker to bypass configured security policies. If the action in case of Cisco UTD Snort IPS Engine failure is set to fail-close, successful exploitation of this vulnerability could cause traffic that is configured to be inspected by Cisco UTD Snort IPS Engine to be dropped.

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 2 y ago (2024-09-25)

Exploit prediction

0.42% chance of exploitation in the next 30 days, higher than 36% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	5.8	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N
NVD	3.1	6.5	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:L

Affected products

Cisco Cisco UTD SNORT IPS Engine Software
cisco cisco_utd_snort_ips_engine_software

Classification

Weakness

CWE-122 Heap-based Buffer Overflow
CWE-787 Out-of-bounds Write

References

sec.cloudapps.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-utd-snort3-dos-bypas-b4OUEwxD
vendor-advisory

Sources

CVE List CVE-2024-20508
NVD CVE-2024-20508

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Summary