CVE-2026-20221

Multiple Cisco Products Snort 3 Generic Routing Encapsulation Denial of Service Vulnerabilities

Published Oct 21, 2026 CVSS 3.1 · 5.8 Medium EPSS < 1% KEV · Not listed

Description

Multiple Cisco products are affected by a vulnerability in the generic routing encapsulation (GRE) tunnel decapsulation feature of the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause an unexpected restart of the Snort 3 Detection Engine.

This vulnerability is due to improper handling of nested GRE traffic. An attacker could exploit this vulnerability by sending a crafted GRE payload through an affected device. A successful exploit could allow the attacker to trigger an unexpected reload of the Snort 3 Detection Engine, resulting in either a bypass or denial of service (DoS) condition, depending on device configuration. For more information, see the section of this advisory. The Snort 3 Detection Engine will restart automatically. No manual intervention is required.

Affected Products

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions

Cisco

Cisco Cyber Vision

unknown

Version	Status	Constraints
`3.0.0`	affected	—
`3.0.2`	affected	—
`3.0.3`	affected	—
`3.0.1`	affected	—
`3.1.0`	affected	—
`3.0.4`	affected	—
`3.1.1`	affected	—
`3.1.2`	affected	—
`3.2.0`	affected	—
`3.0.5`	affected	—
`3.2.1`	affected	—
`3.0.6`	affected	—
`3.2.2`	affected	—
`3.2.3`	affected	—
`3.2.4`	affected	—
`4.0.0`	affected	—
`4.0.1`	affected	—
`4.0.2`	affected	—
`4.0.3`	affected	—
`4.1.0`	affected	—
`4.1.1`	affected	—
`4.1.2`	affected	—
`4.1.3`	affected	—
`4.1.4`	affected	—
`4.2.0`	affected	—
`4.2.1`	affected	—
`4.1.5`	affected	—
`4.2.2`	affected	—
`4.2.X`	affected	—
`4.2.3`	affected	—
`4.2.4`	affected	—
`4.2.6`	affected	—
`4.1.6`	affected	—
`4.3.0`	affected	—
`4.3.1`	affected	—
`4.3.2`	affected	—
`4.3.3`	affected	—
`4.4.0`	affected	—
`4.4.1`	affected	—
`4.4.2`	affected	—
`4.4.3`	affected	—
`4.1.7`	affected	—
`5.0.0`	affected	—
`5.0.1`	affected	—
`5.0.2`	affected	—
`5.1.0`	affected	—
`5.1.1`	affected	—
`5.1.2`	affected	—
`5.1.3`	affected	—
`5.2.0`	affected	—
`5.2.1`	affected	—
`5.3.0`	affected	—
`5.3.1`	affected	—
`5.3.2`	affected	—
`5.3.3`	affected	—
`5.5.1`	affected	—
`5.6.1`	affected	—
`5.6.0`	affected	—
`5.4.0`	affected	—
`5.4.1`	affected	—
`5.4.2`	affected	—

Cisco

Cisco Open Source Snort3

unknown

Version	Status	Constraints
`3.12.2.0`	affected	—
`3.1.2.0`	affected	—
`3.1.3.0`	affected	—
`3.1.4.0`	affected	—
`3.1.5.0`	affected	—
`3.1.6.0`	affected	—
`3.1.7.0`	affected	—
`3.1.8.0`	affected	—
`3.1.9.0`	affected	—
`3.1.10.0`	affected	—
`3.1.12.0`	affected	—
`3.1.13.0`	affected	—
`3.1.14.0`	affected	—
`3.1.15.0`	affected	—
`3.1.16.0`	affected	—
`3.1.17.0`	affected	—
`3.1.18.0`	affected	—
`3.1.19.0`	affected	—
`3.1.20.0`	affected	—
`3.1.21.0`	affected	—
`3.1.22.0`	affected	—
`3.1.23.0`	affected	—
`3.1.24.0`	affected	—
`3.1.25.0`	affected	—
`3.1.27.0`	affected	—
`3.1.28.0`	affected	—
`3.1.29.0`	affected	—
`3.1.30.0`	affected	—
`3.1.31.0`	affected	—
`3.1.32.0`	affected	—
`3.1.36.0`	affected	—
`3.1.38.0`	affected	—
`3.1.39.0`	affected	—
`3.1.40.0`	affected	—
`3.1.41.0`	affected	—
`3.1.42.0`	affected	—
`3.1.43.0`	affected	—
`3.1.45.0`	affected	—
`3.1.47.0`	affected	—
`3.1.48.0`	affected	—
`3.1.50.0`	affected	—
`3.1.51.0`	affected	—
`3.1.52.0`	affected	—
`3.1.53.0`	affected	—
`3.1.55.0`	affected	—
`3.1.56.0`	affected	—
`3.1.57.0`	affected	—
`3.1.58.0`	affected	—
`3.1.59.0`	affected	—
`3.1.60.0`	affected	—
`3.1.61.0`	affected	—
`3.1.62.0`	affected	—
`3.1.63.0`	affected	—
`3.1.64.0`	affected	—
`3.1.65.0`	affected	—
`3.1.66.0`	affected	—
`3.1.67.0`	affected	—
`3.1.69.0`	affected	—
`3.1.70.0`	affected	—
`3.1.71.0`	affected	—
`3.1.72.0`	affected	—
`3.1.73.0`	affected	—
`3.1.74.0`	affected	—
`3.1.75.0`	affected	—
`3.1.76.0`	affected	—
`3.1.77.0`	affected	—
`3.1.78.0`	affected	—
`3.1.81.0`	affected	—
`3.1.82.0`	affected	—
`3.1.83.0`	affected	—
`3.1.84.0`	affected	—
`3.2.1.0`	affected	—
`3.2.2.0`	affected	—
`3.3.0.0`	affected	—
`3.3.1.0`	affected	—
`3.3.2.0`	affected	—
`3.3.3.0`	affected	—
`3.3.4.0`	affected	—
`3.3.5.0`	affected	—
`3.3.7.0`	affected	—
`3.5.0.0`	affected	—
`3.5.1.0`	affected	—
`3.8.1.0`	affected	—
`3.6.0.0`	affected	—
`3.6.2.0`	affected	—
`3.9.3.0`	affected	—
`3.7.2.0`	affected	—
`3.7.0.0`	affected	—
`3.9.6.0`	affected	—
`3.10.0.0`	affected	—
`3.10.2.0`	affected	—
`3.7.4.0`	affected	—
`3.9.0.0`	affected	—
`3.5.2.0`	affected	—
`3.12.1.0`	affected	—
`3.6.1.0`	affected	—
`3.9.2.0`	affected	—
`3.6.3.0`	affected	—
`3.9.5.0`	affected	—
`3.7.1.0`	affected	—
`3.9.7.0`	affected	—
`3.7.3.0`	affected	—
`3.10.1.0`	affected	—
`3.9.1.0`	affected	—
`3.11.1.0`	affected	—

Cisco

Cisco Secure Firewall Threat Defense (FTD) Software

unknown

Version	Status	Constraints
`7.0.0`	affected	—
`7.0.0.1`	affected	—
`7.0.1`	affected	—
`7.0.1.1`	affected	—
`7.0.2`	affected	—
`7.2.0`	affected	—
`7.0.2.1`	affected	—
`7.0.3`	affected	—
`7.2.0.1`	affected	—
`7.0.4`	affected	—
`7.2.1`	affected	—
`7.0.5`	affected	—
`7.3.0`	affected	—
`7.2.2`	affected	—
`7.2.3`	affected	—
`7.3.1`	affected	—
`7.2.4`	affected	—
`7.0.6`	affected	—
`7.2.5`	affected	—
`7.2.4.1`	affected	—
`7.3.1.1`	affected	—
`7.4.0`	affected	—
`7.0.6.1`	affected	—
`7.2.5.1`	affected	—
`7.4.1`	affected	—
`7.2.6`	affected	—
`7.0.6.2`	affected	—
`7.4.1.1`	affected	—
`7.2.7`	affected	—
`7.2.5.2`	affected	—
`7.3.1.2`	affected	—
`7.2.8`	affected	—
`7.6.0`	affected	—
`7.4.2`	affected	—
`7.2.8.1`	affected	—
`7.0.6.3`	affected	—
`7.4.2.1`	affected	—
`7.2.9`	affected	—
`7.0.7`	affected	—
`7.7.0`	affected	—
`7.4.2.2`	affected	—
`7.2.10`	affected	—
`7.6.1`	affected	—
`7.4.2.3`	affected	—
`7.0.8`	affected	—
`7.6.2`	affected	—
`7.7.10`	affected	—
`7.7.11`	affected	—
`7.0.8.1`	affected	—
`7.6.2.1`	affected	—
`7.7.10.1`	affected	—
`7.4.2.4`	affected	—
`7.2.10.2`	affected	—
`7.4.3`	affected	—
`7.6.4`	affected	—
`10.0.0`	affected	—
`7.4.4`	affected	—
`7.0.9`	affected	—
`7.2.11`	affected	—
`7.4.7`	affected	—

Cisco

Cisco Umbrella Insights Virtual Appliance

unknown

Version	Status	Constraints
`2.6.0`	affected	—
`2.5.6`	affected	—
`2.5`	affected	—
`2.4.12`	affected	—
`2.7`	affected	—
`2.6.2`	affected	—
`2.5.5`	affected	—
`2.5.4`	affected	—
`2.8`	affected	—
`2.6.1`	affected	—
`2.5.7`	affected	—
`1.5.4`	affected	—
`1.5.5`	affected	—
`1.5.6`	affected	—
`2.0.0`	affected	—
`2.0.2`	affected	—
`2.0.3`	affected	—
`2.1.0`	affected	—
`2.1.2`	affected	—
`2.1.4`	affected	—
`2.1.5`	affected	—
`2.2`	affected	—
`2.2.1`	affected	—
`2.3`	affected	—
`2.3.1`	affected	—
`2.4`	affected	—
`2.4.4`	affected	—
`2.4.6`	affected	—
`2.8.9`	affected	—
`3.0`	affected	—
`3.1`	affected	—
`3.2`	affected	—
`2.8.1`	affected	—
`2.8.2`	affected	—
`2.8.3`	affected	—
`2.8.4`	affected	—
`2.8.5`	affected	—
`3.0.1`	affected	—
`3.0.2`	affected	—
`3.0.4`	affected	—
`3.0.5`	affected	—
`3.1.1`	affected	—
`3.1.2`	affected	—
`3.1.3`	affected	—
`3.1.4`	affected	—
`3.2.1`	affected	—
`3.2.2`	affected	—
`3.2.3`	affected	—
`3.3`	affected	—
`3.3.1`	affected	—
`3.3.2`	affected	—
`3.3.3`	affected	—
`3.3.4`	affected	—
`3.4`	affected	—
`3.4.1`	affected	—
`3.4.2`	affected	—
`3.4.3`	affected	—
`3.4.4`	affected	—
`3.4.5`	affected	—
`3.4.6`	affected	—
`3.5`	affected	—
`2.7.1`	affected	—
`2.7.2`	affected	—
`2.7.6`	affected	—
`2.7.9`	affected	—
`2.7.10`	affected	—
`3.5.1`	affected	—
`3.5.2`	affected	—
`3.6.1`	affected	—
`3.6.2`	affected	—
`3.7`	affected	—
`3.7.1`	affected	—
`3.8.3`	affected	—

Cisco

Cisco UTD SNORT IPS Engine Software

unknown

Version	Status	Constraints
`3.17.1S`	affected	—
`16.12.3`	affected	—
`Fuji-16.9.5`	affected	—
`16.12.4`	affected	—
`17.3.1a`	affected	—
`16.6.6`	affected	—
`16.12.2`	affected	—
`Fuji-16.9.6`	affected	—
`3.17.0S`	affected	—
`Fuji-16.9.3`	affected	—
`Denali-16.3.7`	affected	—
`Fuji-16.9.2`	affected	—
`Fuji-16.9.4`	affected	—
`Everest-16.6.4`	affected	—
`Everest-16.6.3`	affected	—
`16.6.5`	affected	—
`Denali-16.3.5`	affected	—
`17.2.1r`	affected	—
`17.1.1`	affected	—
`Everest-16.6.2`	affected	—
`16.6.7a`	affected	—
`Denali-16.3.4`	affected	—
`16.6.1`	affected	—
`Denali-16.3.9`	affected	—
`Denali-16.3.3`	affected	—
`16.12.1a`	affected	—
`17.3.2`	affected	—
`17.4.1a`	affected	—
`16.12.5`	affected	—
`17.5.1`	affected	—
`Fuji-16.9.7`	affected	—
`16.6.9`	affected	—
`17.3.3`	affected	—
`17.5.1a`	affected	—
`17.3.4`	affected	—
`17.3.4a`	affected	—
`17.4.2`	affected	—
`17.4.1b`	affected	—
`17.6.1a`	affected	—
`16.6.10`	affected	—
`17.7.1a`	affected	—
`16.12.6`	affected	—
`Fuji-16.9.8`	affected	—
`17.6.2`	affected	—
`17.8.1a`	affected	—
`16.12.7`	affected	—
`17.3.5`	affected	—
`17.6.3`	affected	—
`17.6.3a`	affected	—
`17.7.2`	affected	—
`17.9.1a`	affected	—
`17.6.4`	affected	—
`17.10.1a`	affected	—
`17.3.6`	affected	—
`16.12.8`	affected	—
`17.3.7`	affected	—
`17.9.2a`	affected	—
`17.6.5`	affected	—
`17.11.1a`	affected	—
`17.9.3a`	affected	—
`17.12.1a`	affected	—
`17.9.4`	affected	—
`17.6.6`	affected	—
`17.3.8`	affected	—
`17.3.8a`	affected	—
`17.6.6a`	affected	—
`17.9.4a`	affected	—
`17.12.2`	affected	—
`17.13.1a`	affected	—
`17.9.5a`	affected	—
`17.12.3`	affected	—
`17.6.7`	affected	—
`17.14.1a`	affected	—
`17.12.4`	affected	—
`17.12.3a`	affected	—
`17.15.1a`	affected	—
`17.6.8`	affected	—
`17.9.6`	affected	—
`17.6.8a`	affected	—
`17.16.1a`	affected	—
`17.9.5e`	affected	—
`17.12.4a`	affected	—
`17.15.2c`	affected	—
`17.9.5f`	affected	—
`17.12.4b`	affected	—
`17.15.2a`	affected	—
`17.12.5`	affected	—
`17.17.1`	affected	—
`17.12.5a`	affected	—
`17.9.7a`	affected	—
`17.15.3a`	affected	—
`17.15.3`	affected	—
`17.12.5b`	affected	—
`17.12.5c`	affected	—
`17.15.4`	affected	—
`17.9.7b`	affected	—
`17.18.1`	affected	—
`17.18.1a`	affected	—
`17.12.6`	affected	—
`17.9.8`	affected	—
`17.15.4c`	affected	—
`17.12.5d`	affected	—
`17.18.2`	affected	—
`26.1.1`	affected	—
`17.15.5`	affected	—
`17.15.5a`	affected	—
`17.12.7`	affected	—
`17.12.7a`	affected	—
`17.12.7b`	affected	—
`17.9.9`	affected	—
`17.18.3a`	affected	—
`17.12.8`	affected	—
`17.15.6`	affected	—
`17.18.4`	affected	—
`26.1.2`	affected	—
`17.9.10`	affected	—

No data.

Vendor Product Versions

Cisco

Cisco Open Source Snort3

Version	Status	Scheme	Platform
`3.12.2.0`	affected	generic	—
`3.1.2.0`	affected	generic	—
`3.1.3.0`	affected	generic	—
`3.1.4.0`	affected	generic	—
`3.1.5.0`	affected	generic	—
`3.1.6.0`	affected	generic	—
`3.1.7.0`	affected	generic	—
`3.1.8.0`	affected	generic	—
`3.1.9.0`	affected	generic	—
`3.1.10.0`	affected	generic	—
`3.1.12.0`	affected	generic	—
`3.1.13.0`	affected	generic	—
`3.1.14.0`	affected	generic	—
`3.1.15.0`	affected	generic	—
`3.1.16.0`	affected	generic	—
`3.1.17.0`	affected	generic	—
`3.1.18.0`	affected	generic	—
`3.1.19.0`	affected	generic	—
`3.1.20.0`	affected	generic	—
`3.1.21.0`	affected	generic	—
`3.1.22.0`	affected	generic	—
`3.1.23.0`	affected	generic	—
`3.1.24.0`	affected	generic	—
`3.1.25.0`	affected	generic	—
`3.1.27.0`	affected	generic	—
`3.1.28.0`	affected	generic	—
`3.1.29.0`	affected	generic	—
`3.1.30.0`	affected	generic	—
`3.1.31.0`	affected	generic	—
`3.1.32.0`	affected	generic	—
`3.1.36.0`	affected	generic	—
`3.1.38.0`	affected	generic	—
`3.1.39.0`	affected	generic	—
`3.1.40.0`	affected	generic	—
`3.1.41.0`	affected	generic	—
`3.1.42.0`	affected	generic	—
`3.1.43.0`	affected	generic	—
`3.1.45.0`	affected	generic	—
`3.1.47.0`	affected	generic	—
`3.1.48.0`	affected	generic	—
`3.1.50.0`	affected	generic	—
`3.1.51.0`	affected	generic	—
`3.1.52.0`	affected	generic	—
`3.1.53.0`	affected	generic	—
`3.1.55.0`	affected	generic	—
`3.1.56.0`	affected	generic	—
`3.1.57.0`	affected	generic	—
`3.1.58.0`	affected	generic	—
`3.1.59.0`	affected	generic	—
`3.1.60.0`	affected	generic	—
`3.1.61.0`	affected	generic	—
`3.1.62.0`	affected	generic	—
`3.1.63.0`	affected	generic	—
`3.1.64.0`	affected	generic	—
`3.1.65.0`	affected	generic	—
`3.1.66.0`	affected	generic	—
`3.1.67.0`	affected	generic	—
`3.1.69.0`	affected	generic	—
`3.1.70.0`	affected	generic	—
`3.1.71.0`	affected	generic	—
`3.1.72.0`	affected	generic	—
`3.1.73.0`	affected	generic	—
`3.1.74.0`	affected	generic	—
`3.1.75.0`	affected	generic	—
`3.1.76.0`	affected	generic	—
`3.1.77.0`	affected	generic	—
`3.1.78.0`	affected	generic	—
`3.1.81.0`	affected	generic	—
`3.1.82.0`	affected	generic	—
`3.1.83.0`	affected	generic	—
`3.1.84.0`	affected	generic	—
`3.2.1.0`	affected	generic	—
`3.2.2.0`	affected	generic	—
`3.3.0.0`	affected	generic	—
`3.3.1.0`	affected	generic	—
`3.3.2.0`	affected	generic	—
`3.3.3.0`	affected	generic	—
`3.3.4.0`	affected	generic	—
`3.3.5.0`	affected	generic	—
`3.3.7.0`	affected	generic	—
`3.5.0.0`	affected	generic	—
`3.5.1.0`	affected	generic	—
`3.8.1.0`	affected	generic	—
`3.6.0.0`	affected	generic	—
`3.6.2.0`	affected	generic	—
`3.9.3.0`	affected	generic	—
`3.7.2.0`	affected	generic	—
`3.7.0.0`	affected	generic	—
`3.9.6.0`	affected	generic	—
`3.10.0.0`	affected	generic	—
`3.10.2.0`	affected	generic	—
`3.7.4.0`	affected	generic	—
`3.9.0.0`	affected	generic	—
`3.5.2.0`	affected	generic	—
`3.12.1.0`	affected	generic	—
`3.6.1.0`	affected	generic	—
`3.9.2.0`	affected	generic	—
`3.6.3.0`	affected	generic	—
`3.9.5.0`	affected	generic	—
`3.7.1.0`	affected	generic	—
`3.9.7.0`	affected	generic	—
`3.7.3.0`	affected	generic	—
`3.10.1.0`	affected	generic	—
`3.9.1.0`	affected	generic	—
`3.11.1.0`	affected	generic	—

Cisco

Cisco Secure Firewall Threat Defense (ftd) Software

Version	Status	Scheme	Platform
`7.0.0`	affected	semver	—
`7.0.0.1`	affected	generic	—
`7.0.1`	affected	semver	—
`7.0.1.1`	affected	generic	—
`7.0.2`	affected	semver	—
`7.2.0`	affected	semver	—
`7.0.2.1`	affected	generic	—
`7.0.3`	affected	semver	—
`7.2.0.1`	affected	generic	—
`7.0.4`	affected	semver	—
`7.2.1`	affected	semver	—
`7.0.5`	affected	semver	—
`7.3.0`	affected	semver	—
`7.2.2`	affected	semver	—
`7.2.3`	affected	semver	—
`7.3.1`	affected	semver	—
`7.2.4`	affected	semver	—
`7.0.6`	affected	semver	—
`7.2.5`	affected	semver	—
`7.2.4.1`	affected	generic	—
`7.3.1.1`	affected	semver	—
`7.4.0`	affected	semver	—
`7.0.6.1`	affected	semver	—
`7.2.5.1`	affected	semver	—
`7.4.1`	affected	semver	—
`7.2.6`	affected	semver	—
`7.0.6.2`	affected	semver	—
`7.4.1.1`	affected	semver	—
`7.2.7`	affected	semver	—
`7.2.5.2`	affected	semver	—
`7.3.1.2`	affected	semver	—
`7.2.8`	affected	semver	—
`7.6.0`	affected	semver	—
`7.4.2`	affected	semver	—
`7.2.8.1`	affected	semver	—
`7.0.6.3`	affected	semver	—
`7.4.2.1`	affected	semver	—
`7.2.9`	affected	semver	—
`7.0.7`	affected	semver	—
`7.7.0`	affected	semver	—
`7.4.2.2`	affected	semver	—
`7.2.10`	affected	semver	—
`7.6.1`	affected	semver	—
`7.4.2.3`	affected	semver	—
`7.0.8`	affected	semver	—
`7.6.2`	affected	semver	—
`7.7.10`	affected	semver	—
`7.7.11`	affected	semver	—
`7.0.8.1`	affected	semver	—
`7.6.2.1`	affected	semver	—
`7.7.10.1`	affected	semver	—
`7.4.2.4`	affected	semver	—
`7.2.10.2`	affected	semver	—
`7.4.3`	affected	semver	—
`7.6.4`	affected	semver	—
`10.0.0`	affected	semver	—
`7.4.4`	affected	semver	—
`7.0.9`	affected	semver	—
`7.2.11`	affected	semver	—
`7.4.7`	affected	semver	—

Cisco

Cisco Utd Snort Ips Engine Software

Version	Status	Scheme	Platform
`3.17.1S`	affected	generic	—
`16.12.3`	affected	generic	—
`Fuji-16.9.5`	affected	generic	—
`16.12.4`	affected	generic	—
`17.3.1a`	affected	generic	—
`16.6.6`	affected	generic	—
`16.12.2`	affected	generic	—
`Fuji-16.9.6`	affected	generic	—
`3.17.0S`	affected	generic	—
`Fuji-16.9.3`	affected	generic	—
`Denali-16.3.7`	affected	generic	—
`Fuji-16.9.2`	affected	generic	—
`Fuji-16.9.4`	affected	generic	—
`Everest-16.6.4`	affected	generic	—
`Everest-16.6.3`	affected	generic	—
`16.6.5`	affected	generic	—
`Denali-16.3.5`	affected	generic	—
`17.2.1r`	affected	generic	—
`17.1.1`	affected	generic	—
`Everest-16.6.2`	affected	generic	—
`16.6.7a`	affected	generic	—
`Denali-16.3.4`	affected	generic	—
`16.6.1`	affected	generic	—
`Denali-16.3.9`	affected	generic	—
`Denali-16.3.3`	affected	generic	—
`16.12.1a`	affected	generic	—
`17.3.2`	affected	generic	—
`17.4.1a`	affected	generic	—
`16.12.5`	affected	generic	—
`17.5.1`	affected	generic	—
`Fuji-16.9.7`	affected	generic	—
`16.6.9`	affected	generic	—
`17.3.3`	affected	generic	—
`17.5.1a`	affected	generic	—
`17.3.4`	affected	generic	—
`17.3.4a`	affected	generic	—
`17.4.2`	affected	generic	—
`17.4.1b`	affected	generic	—
`17.6.1a`	affected	generic	—
`16.6.10`	affected	generic	—
`17.7.1a`	affected	generic	—
`16.12.6`	affected	generic	—
`Fuji-16.9.8`	affected	generic	—
`17.6.2`	affected	generic	—
`17.8.1a`	affected	generic	—
`16.12.7`	affected	generic	—
`17.3.5`	affected	generic	—
`17.6.3`	affected	generic	—
`17.6.3a`	affected	generic	—
`17.7.2`	affected	generic	—
`17.9.1a`	affected	generic	—
`17.6.4`	affected	generic	—
`17.10.1a`	affected	generic	—
`17.3.6`	affected	generic	—
`16.12.8`	affected	generic	—
`17.3.7`	affected	generic	—
`17.9.2a`	affected	generic	—
`17.6.5`	affected	generic	—
`17.11.1a`	affected	generic	—
`17.9.3a`	affected	generic	—
`17.12.1a`	affected	generic	—
`17.9.4`	affected	generic	—
`17.6.6`	affected	generic	—
`17.3.8`	affected	generic	—
`17.3.8a`	affected	generic	—
`17.6.6a`	affected	generic	—
`17.9.4a`	affected	generic	—
`17.12.2`	affected	generic	—
`17.13.1a`	affected	generic	—
`17.9.5a`	affected	generic	—
`17.12.3`	affected	generic	—
`17.6.7`	affected	generic	—
`17.14.1a`	affected	generic	—
`17.12.4`	affected	generic	—
`17.12.3a`	affected	generic	—
`17.15.1a`	affected	generic	—
`17.6.8`	affected	generic	—
`17.9.6`	affected	generic	—
`17.6.8a`	affected	generic	—
`17.16.1a`	affected	generic	—
`17.9.5e`	affected	generic	—
`17.12.4a`	affected	generic	—
`17.15.2c`	affected	generic	—
`17.9.5f`	affected	generic	—
`17.12.4b`	affected	generic	—
`17.15.2a`	affected	generic	—
`17.12.5`	affected	generic	—
`17.17.1`	affected	generic	—
`17.12.5a`	affected	generic	—
`17.9.7a`	affected	generic	—
`17.15.3a`	affected	generic	—
`17.15.3`	affected	generic	—
`17.12.5b`	affected	generic	—
`17.12.5c`	affected	generic	—
`17.15.4`	affected	generic	—
`17.9.7b`	affected	generic	—
`17.18.1`	affected	generic	—
`17.18.1a`	affected	generic	—
`17.12.6`	affected	generic	—
`17.9.8`	affected	generic	—
`17.15.4c`	affected	generic	—
`17.12.5d`	affected	generic	—
`17.18.2`	affected	generic	—
`26.1.1`	affected	generic	—
`17.15.5`	affected	generic	—
`17.15.5a`	affected	generic	—
`17.12.7`	affected	generic	—
`17.12.7a`	affected	generic	—
`17.12.7b`	affected	generic	—
`17.9.9`	affected	generic	—
`17.18.3a`	affected	generic	—
`17.12.8`	affected	generic	—
`17.15.6`	affected	generic	—
`17.18.4`	affected	generic	—
`26.1.2`	affected	generic	—
`17.9.10`	affected	generic	—

Cisco

Cyber Vision

Version	Status	Scheme	Platform
`3.0.0`	affected	semver	—
`3.0.2`	affected	semver	—
`3.0.3`	affected	semver	—
`3.0.1`	affected	semver	—
`3.1.0`	affected	semver	—
`3.0.4`	affected	semver	—
`3.1.1`	affected	semver	—
`3.1.2`	affected	semver	—
`3.2.0`	affected	semver	—
`3.0.5`	affected	semver	—
`3.2.1`	affected	semver	—
`3.0.6`	affected	semver	—
`3.2.2`	affected	semver	—
`3.2.3`	affected	semver	—
`3.2.4`	affected	semver	—
`4.0.0`	affected	semver	—
`4.0.1`	affected	semver	—
`4.0.2`	affected	semver	—
`4.0.3`	affected	semver	—
`4.1.0`	affected	semver	—
`4.1.1`	affected	semver	—
`4.1.2`	affected	semver	—
`4.1.3`	affected	semver	—
`4.1.4`	affected	semver	—
`4.2.0`	affected	semver	—
`4.2.1`	affected	semver	—
`4.1.5`	affected	semver	—
`4.2.2`	affected	semver	—
`4.2.X`	affected	generic	—
`4.2.3`	affected	semver	—
`4.2.4`	affected	semver	—
`4.2.6`	affected	semver	—
`4.1.6`	affected	semver	—
`4.3.0`	affected	semver	—
`4.3.1`	affected	semver	—
`4.3.2`	affected	semver	—
`4.3.3`	affected	semver	—
`4.4.0`	affected	semver	—
`4.4.1`	affected	semver	—
`4.4.2`	affected	semver	—
`4.4.3`	affected	semver	—
`4.1.7`	affected	semver	—
`5.0.0`	affected	semver	—
`5.0.1`	affected	semver	—
`5.0.2`	affected	semver	—
`5.1.0`	affected	semver	—
`5.1.1`	affected	semver	—
`5.1.2`	affected	semver	—
`5.1.3`	affected	semver	—
`5.2.0`	affected	semver	—
`5.2.1`	affected	semver	—
`5.3.0`	affected	semver	—
`5.3.1`	affected	semver	—
`5.3.2`	affected	semver	—
`5.3.3`	affected	semver	—
`5.5.1`	affected	semver	—
`5.6.1`	affected	semver	—
`5.6.0`	affected	semver	—
`5.4.0`	affected	semver	—
`5.4.1`	affected	semver	—
`5.4.2`	affected	semver	—

Cisco

Secure Firewall Threat Defense

Version	Status	Scheme	Platform
`7.0.0`	affected	semver	—
`7.0.0.1`	affected	generic	—
`7.0.1`	affected	semver	—
`7.0.1.1`	affected	generic	—
`7.0.2`	affected	semver	—
`7.2.0`	affected	semver	—
`7.0.2.1`	affected	generic	—
`7.0.3`	affected	semver	—
`7.2.0.1`	affected	generic	—
`7.0.4`	affected	semver	—
`7.2.1`	affected	semver	—
`7.0.5`	affected	semver	—
`7.3.0`	affected	semver	—
`7.2.2`	affected	semver	—
`7.2.3`	affected	semver	—
`7.3.1`	affected	semver	—
`7.2.4`	affected	semver	—
`7.0.6`	affected	semver	—
`7.2.5`	affected	semver	—
`7.2.4.1`	affected	generic	—
`7.3.1.1`	affected	semver	—
`7.4.0`	affected	semver	—
`7.0.6.1`	affected	semver	—
`7.2.5.1`	affected	semver	—
`7.4.1`	affected	semver	—
`7.2.6`	affected	semver	—
`7.0.6.2`	affected	semver	—
`7.4.1.1`	affected	semver	—
`7.2.7`	affected	semver	—
`7.2.5.2`	affected	semver	—
`7.3.1.2`	affected	semver	—
`7.2.8`	affected	semver	—
`7.6.0`	affected	semver	—
`7.4.2`	affected	semver	—
`7.2.8.1`	affected	semver	—
`7.0.6.3`	affected	semver	—
`7.4.2.1`	affected	semver	—
`7.2.9`	affected	semver	—
`7.0.7`	affected	semver	—
`7.7.0`	affected	semver	—
`7.4.2.2`	affected	semver	—
`7.2.10`	affected	semver	—
`7.6.1`	affected	semver	—
`7.4.2.3`	affected	semver	—
`7.0.8`	affected	semver	—
`7.6.2`	affected	semver	—
`7.7.10`	affected	semver	—
`7.7.11`	affected	semver	—
`7.0.8.1`	affected	semver	—
`7.6.2.1`	affected	semver	—
`7.7.10.1`	affected	semver	—
`7.4.2.4`	affected	semver	—
`7.2.10.2`	affected	semver	—
`7.4.3`	affected	semver	—
`7.6.4`	affected	semver	—
`10.0.0`	affected	semver	—
`7.4.4`	affected	semver	—
`7.0.9`	affected	semver	—
`7.2.11`	affected	semver	—
`7.4.7`	affected	semver	—

Cisco

Umbrella Insights Virtual Appliance

Version	Status	Scheme	Platform
`2.6.0`	affected	semver	—
`2.5.6`	affected	semver	—
`2.5`	affected	generic	—
`2.6`	affected	generic	—
`2.4.12`	affected	semver	—
`2.7`	affected	semver	—
`2.6.2`	affected	semver	—
`2.6.1`	affected	semver	—
`2.5.7`	affected	semver	—
`1.5.4`	affected	semver	—
`1.5.5`	affected	semver	—
`1.5.6`	affected	semver	—
`2.0.0`	affected	semver	—
`2.0.2`	affected	semver	—
`2.0.3`	affected	semver	—
`2.1.0`	affected	semver	—
`2.1.2`	affected	semver	—
`2.1.4`	affected	semver	—
`2.1.5`	affected	semver	—
`2.2`	affected	semver	—
`2.2.1`	affected	semver	—
`2.3`	affected	semver	—
`2.3.1`	affected	semver	—
`2.4`	affected	generic	—
`2.4.4`	affected	semver	—
`2.4.6`	affected	semver	—
`2.8`	affected	semver	—
`3.0`	affected	generic	—
`3.0.1`	affected	semver	—
`3.0.2`	affected	semver	—
`3.0.3`	affected	semver	—
`3.0.4`	affected	semver	—
`3.1.1`	affected	semver	—
`3.1.2`	affected	semver	—
`3.1.3`	affected	semver	—
`3.1.4`	affected	semver	—
`3.1.5`	affected	semver	—
`3.2.1`	affected	semver	—
`3.2.2`	affected	semver	—
`3.2.3`	affected	semver	—
`3.3`	affected	semver	—
`3.3.1`	affected	semver	—
`3.3.2`	affected	semver	—
`3.3.3`	affected	semver	—
`3.4`	affected	semver	—
`3.4.1`	affected	semver	—
`3.4.2`	affected	semver	—
`3.4.3`	affected	semver	—
`3.4.4`	affected	semver	—
`3.4.5`	affected	semver	—
`3.4.6`	affected	semver	—
`3.5`	affected	semver	—
`2.7.1`	affected	semver	—
`2.7.2`	affected	semver	—
`2.7.6`	affected	semver	—
`2.7.9`	affected	semver	—
`2.7.10`	affected	semver	—
`3.5.1`	affected	semver	—
`3.5.2`	affected	semver	—
`3.6.1`	affected	semver	—
`3.6.2`	affected	semver	—
`3.7`	affected	semver	—
`3.7.1`	affected	semver	—
`3.8.3`	affected	semver	—

Remediation

No solution or workaround provided in the CVE record

Tracking

Advisories

No advisories available

Metrics

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required None

Scope Changed

Confidentiality Impact None

Integrity Impact None

Availability Impact Low

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Exploit prediction score: < 1% (0.577% probability within 30 days)

Exploitation none

Automatable yes

Technical Impact partial

References

Link	Providers
https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-gre-JNpMHrTv

History

Oct 23, 2026 12:45 AM First appearance in the feed. Affected vendors updated View changes

Type	Values Removed	Values Added
First Time appeared		Cisco Cisco cisco Open Source Snort3 Cisco cisco Secure Firewall Threat Defense (ftd) Software Cisco cisco Utd Snort Ips Engine Software Cisco cyber Vision Cisco secure Firewall Threat Defense Cisco umbrella Insights Virtual Appliance
Vendors & Products		Cisco Cisco cisco Open Source Snort3 Cisco cisco Secure Firewall Threat Defense (ftd) Software Cisco cisco Utd Snort Ips Engine Software Cisco cyber Vision Cisco secure Firewall Threat Defense Cisco umbrella Insights Virtual Appliance

Oct 22, 2026 2:30 PM Scoring metrics updated View changes

Type	Values Removed	Values Added
Metrics		ssvc `{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}`

Oct 21, 2026 5:15 PM Description updated. Title updated. Weaknesses updated. Added references. Scoring metrics updated View changes

Type	Values Removed	Values Added
Description		Multiple Cisco products are affected by a vulnerability in the generic routing encapsulation (GRE) tunnel decapsulation feature of the Snort 3 Detection Engine that could allow an unauthenticated, remote attacker to cause an unexpected restart of the Snort 3 Detection Engine. This vulnerability is due to improper handling of nested GRE traffic. An attacker could exploit this vulnerability by sending a crafted GRE payload through an affected device. A successful exploit could allow the attacker to trigger an unexpected reload of the Snort 3 Detection Engine, resulting in either a bypass or denial of service (DoS) condition, depending on device configuration. For more information, see the section of this advisory. The Snort 3 Detection Engine will restart automatically. No manual intervention is required.
Title		Multiple Cisco Products Snort 3 Generic Routing Encapsulation Denial of Service Vulnerabilities
Weaknesses		CWE-476
References		https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-gre-JNpMHrTv
Metrics		cvssV3_1 `{'score': 5.8, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L'}`

Subscriptions

Cisco Cisco Open Source Snort3 Cisco Secure Firewall Threat Defense (ftd) Software Cisco Utd Snort Ips Engine Software Cyber Vision Secure Firewall Threat Defense Umbrella Insights Virtual Appliance

Weaknesses