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Medium 5.8Published Oct 21, 2026

CVE-2026-20179Multiple Cisco Products Snort 3 Generic Routing Encapsulation Denial of Service Vulnerabilities

Updated under an hour ago ()

Does this affect you?

It affects Cisco Open Source Snort3 and 2 other products. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Multiple Cisco products are affected by a vulnerability in the Snort 3 Generic Routing Encapsulation (GRE) 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 incomplete error checking when Snort 3 parses GRE packets. An attacker could exploit this vulnerability by sending a crafted GRE packet to a targeted device to be parsed by Snort. A successful exploit could allow the attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a DoS condition.

CVSS
5.8 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L
Weakness (CWE)
CWE-128
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
cisco
NVD analysis
Awaiting Analysis
Record last updated
Oct 21, 2026
First seen by InfoSec Signals
Oct 21, 2026

Affected products

Affected products
Cisco Cisco Open Source Snort3
cisco:open_source_snort3 (from the name)
3.12.2.0; 3.1.2.0; 3.1.3.0; 3.1.4.0; 3.1.5.0; 3.1.6.0; 3.1.7.0; 3.1.8.0; and 97 more ranges
CNA record
Cisco Cisco Secure Firewall Threat Defense (FTD) Software
cisco:secure_firewall_threat_defense_ftd_software (from the name)
7.0.0; 7.0.0.1; 7.0.1; 7.0.1.1; 7.0.2; 7.2.0; 7.0.2.1; 7.0.3; and 52 more ranges
CNA record
Cisco Cisco UTD SNORT IPS Engine Software
cisco:utd_snort_ips_engine_software (from the name)
17.12.1a; 17.12.2; 17.13.1a; 17.12.3; 17.14.1a; 17.12.4; 17.12.3a; 17.15.1a; and 30 more ranges
CNA record

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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