CVE Catalog

CVE-2026-20179

MediumCVSS 5.8
Published: Updated: Translated: NVD NIST

Exploitation Probability (EPSS)

Low risk
0.39%

32th percentile - higher than 32% of all known CVEs

Summary

A vulnerability in the Snort 3 Generic Routing Encapsulation (GRE) Detection Engine of multiple Cisco products allows an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart, interrupting packet inspection. The flaw is due to incomplete error checking when parsing GRE packets. Sending a crafted GRE packet to a targeted device can cause an unexpected restart and DoS condition.

Risk Assessment

An attacker could remotely, without authentication, force the Snort 3 Detection Engine to restart, interrupting packet inspection and potentially degrading network security. This could be exploited to disrupt protection systems.

Recommendation

Update Cisco products using Snort 3 to a fixed version. Consider temporarily disabling or restricting GRE inspection if feasible until the update is applied.

Other vulnerabilities in Snort 3

See all
Original NVD description (English source)

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.

Vulnerability data from NVD (NIST) · CISA KEV · EPSS