CVE-2026-76445 Cisco CVE debrief

Who should care

Defenders of Cisco Open Source Snort3, Cisco Secure Firewall Threat Defense (FTD) Software, and Cisco UTD SNORT IPS Engine Software should verify and apply patches to prevent potential DoS attacks.

Why it matters

A vulnerability in the Snort 3 Detection Engine could allow an unauthenticated, remote attacker to cause a denial of service (DoS) condition. Defenders of affected products should verify and apply patches to prevent potential DoS attacks.

• Verify and apply patches to prevent potential DoS attacks
• Monitor for crafted, fragmented UDP datagrams containing GPRS Tunneling Protocol (GTP) extension headers
• Implement compensating controls to detect and prevent potential DoS attacks

Technical summary

The vulnerability is due to a flaw in logic handling when General Packet Radio Service (GPRS) Tunneling Protocol (GTP) extension headers are processed within the codec. An attacker could exploit this vulnerability by sending a crafted, fragmented UDP datagram that contains these headers to the Snort 3 Detection Engine of an affected device, potentially impacting Cisco Open Source Snort3, Cisco Secure Firewall Threat Defense (FTD) Software, and Cisco UTD SNORT IPS Engine Software. Defenders should focus on verifying and applying patches.

Defensive priority

Medium priority for defenders of Cisco Open Source Snort3, Cisco Secure Firewall Threat Defense (FTD) Software, and Cisco UTD SNORT IPS Engine Software to verify and apply patches.

Recommended defensive actions

• Verify and apply patches for Cisco Open Source Snort3, Cisco Secure Firewall Threat Defense (FTD) Software, and Cisco UTD SNORT IPS Engine Software
• Monitor for crafted, fragmented UDP datagrams containing GPRS Tunneling Protocol (GTP) extension headers
• Implement compensating controls to detect and prevent potential DoS attacks
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The CVE record and source item provide details on the vulnerability, affected products, and potential impact. However, there is limited information on exploitation, victims, or business impact. Defenders should verify patches for Cisco Open Source Snort3, Cisco Secure Firewall Threat Defense (FTD) Software, and Cisco UTD SNORT IPS Engine Software. Evidence is limited to CVE and source item details.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.