Cisco Secure Firewall Threat Defense Software Snort 3 Memory Management Denial of Service Vulnerability

published 2026-03-04 8 mo ago modified 2026-08-20 2 mo ago also EUVD-2026-9458

cvss: 5.8; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.5%; EPSS 0.5% chance of exploitation in 30 days, percentile 40%
public exploits: 0; none known

A vulnerability in the memory management handling for the Snort 3 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart.

This vulnerability is due to a logic error in memory management when a device is performing Snort 3 SSL packet inspection. An attacker could exploit this vulnerability by sending crafted SSL packets through an established connection to be parsed by the Snort 3 Detection Engine. A successful exploit could allow the attacker to cause a denial of service (DoS) condition when the Snort 3 Detection Engine unexpectedly restarts.

CISA SSVC

Exploitation: none
Automatable: yes
Technical impact: partial
Assessed: 8 mo ago (2026-03-04)

Exploit prediction

0.46% chance of exploitation in the next 30 days, higher than 40% 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:N/A:L

Affected products

Cisco Cisco Secure Firewall Threat Defense (FTD) Software

Classification

Weakness

CWE-788 Access of Memory Location After End of Buffer

References

sec.cloudapps.cisco.com /security/center/content/CiscoSecurityAdvisory/cisco-sa-ftd-snort3ssl-FBEKYXpH
vendor-advisory

Sources

CVE List CVE-2026-20052
NVD CVE-2026-20052

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Summary