TI-2021-17311 Aliases CVE-2021-40116 GHSA-w5gp-j3p5-92ch

Multiple Cisco Products Snort Rule Denial of Service Vulnerability

MEDIUM 46CWE-241Published 2021-10-27 · Updated 2024-11-07

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: —
Confidentiality · integrity · availability: None · None · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA.

Summary

Multiple Cisco products are affected by a vulnerability in Snort rules that could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition on an affected device.The vulnerability is due to improper handling of the Block with Reset or Interactive Block with Reset actions if a rule is configured without proper constraints. An attacker could exploit this vulnerability by sending a crafted IP packet to the affected device. A successful exploit could allow the attacker to cause through traffic to be dropped. Note: Only products with Snort3 configured and either a rule with Block with Reset or Interactive Block with Reset actions configured are vulnerable. Products configured with Snort2 are not vulnerable.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV

EPSS 0.01391 72nd percentileScored 2026-11-07

Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation: None
Automatable: Yes
Technical impact: Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
Cisco	Cisco Firepower Threat Defense Software	all versions	—	No fix listed	CNA

Cisco Firepower Threat Defense Software VendorCisco Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 3

CPE	Versions	Role	Vendor
cpe:2.3:a:cisco:secure_firewall_management_center:3.1.0.1:::::::*	3.1.0.1	Vulnerable	Cisco
cpe:2.3:a:cisco:secure_firewall_threat_defense::::::::	6.4.0 to before 6.4.0.13; 6.6.0 to before 6.6.5.1; 6.7.0 to before 6.7.0.3; 7.0.0 to before 7.0.1	Vulnerable	Cisco
cpe:2.3:a:cisco:snort::::::::	3.0.0.0 to before 3.1.0.100	Vulnerable	Cisco

cpe:2.3:a:cisco:secure_firewall_management_center:3.1.0.1:*:*:*:*:*:*:* Versions 3.1.0.1 Vulnerable ·Cisco
cpe:2.3:a:cisco:secure_firewall_threat_defense:*:*:*:*:*:*:*:* Versions 6.4.0 to before 6.4.0.13; 6.6.0 to before 6.6.5.1; 6.7.0 to before 6.7.0.3; 7.0.0 to before 7.0.1 Vulnerable ·Cisco
cpe:2.3:a:cisco:snort:*:*:*:*:*:*:*:* Versions 3.0.0.0 to before 3.1.0.100 Vulnerable ·Cisco

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2021-40116
2026-10-03 Alias added: GHSA-w5gp-j3p5-92ch

References

Advisory 1

20211027 Multiple Cisco Products Snort Rule Denial of Service Vulnerability

TI-2026-16344 Cisco Secure Firewall Management Center Software Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 10.0
TI-2026-16292 Cisco Secure Firewall Management Center Authentication Bypass Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 10.0
TI-2026-16502 Cisco Secure Firewall Management Center Software Static Credential Vulnerability KEVCVSS 3.1MEDIUM 5.3
TI-2016-05515 The Threat Management Console in Cisco Firepower Management Center 5.2.0 through 6.0.1… CVSS 3.1HIGH 8.8
TI-2025-14563 Cisco Secure Firewall Management Center Software Radius Remote Code Execution Vulnerability CVSS 3.1CRITICAL 10.0
TI-2023-06757 Improper privilege management in Cisco Firepower Management Center CVSS 3.1CRITICAL 9.9

See all 186 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences