Medium severity · published Mar 4, 2026
CVE-2026-20065
Multiple Cisco Products Snort 3 TBD Denial of Service Vulnerability
5.8
CVSS
0.4%
EPSS
No
On KEV
Description
Multiple Cisco products are affected by a vulnerability in the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, resulting in an interruption of packet inspection.
This vulnerability is due to an error in the binder module initialization logic of the Snort Detection Engine. An attacker could exploit this vulnerability by sending certain packets through an established connection that is parsed by Snort 3. A successful exploit could allow the attacker to cause a DoS condition when the Snort 3 Detection Engine restarts unexpectedly.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Changed
Exploitation
Is it being used?
Exploit prediction (EPSS)0.4% · higher than 33% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
CS
Cisco Secure Firewall Threat Defense (FTD) Software · Cisco
7.0.0; 7.0.0.1; 7.0.1; 7.1.0; 7.0.1.1; 7.1.0.1; +34 more · source: vendor
CU
Cisco UTD SNORT IPS Engine Software · Cisco
17.3.1a; 17.2.1r; 17.3.2; 17.4.1a; 17.5.1; 17.3.3; +34 more · source: vendor
SF
Secure Firewall Threat Defense · Cisco
7.0.0; 7.0.0.1; 7.0.1; 7.0.1.1; 7.0.2; 7.0.2.1; +34 more · source: NVD
SN
Snort · Cisco
3.0.0-233 before 3.6.3.0 · source: NVD
UT
Unified Threat Defense Snort Intrusion Prevention System Engine · Cisco
17.2.1r; 17.3.1a; 17.3.2; 17.3.3; 17.3.4; 17.3.4a; +34 more · source: NVD
Affected product
CS
Cisco Secure Firewall Threat Defense (FTD) Software
Cisco
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-20065
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-20065
Vendor Advisory
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-multi-dos-XFWkWSwz
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