Cisco Snort 3 DoS via MDNS HTTP Header Parsing
CVE-2026-20067 Published on March 4, 2026

Multiple Cisco Products Snort 3 TBD Denial of Service Vulnerability
Multiple Cisco products are affected by a vulnerability in the Snort 3 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 parsing the Multicast DNS fields of the HTTP header. An attacker could exploit this vulnerability by sending crafted HTTP packets through an established connection to be parsed by Snort 3. A successful exploit could allow the attacker to cause a DoS condition when the Snort 3 Detection Engine unexpectedly restarts.

NVD

Vulnerability Analysis

CVE-2026-20067 can be exploited with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
CHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
LOW

Weakness Type

What is a Memory Corruption Vulnerability?

The software writes data past the end, or before the beginning, of the intended buffer. Typically, this can result in corruption of data, a crash, or code execution. The software may modify an index or perform pointer arithmetic that references a memory location that is outside of the boundaries of the buffer. A subsequent write operation then produces undefined or unexpected results.

CVE-2026-20067 has been classified to as a Memory Corruption vulnerability or weakness.


Products Associated with CVE-2026-20067

Want to know whenever a new CVE is published for Cisco Cyber Vision? stack.watch will email you.

Cisco Cyber Vision
 

Affected Versions

Cisco Cyber Vision: Cisco Secure Firewall Threat Defense (FTD) Software: Cisco UTD SNORT IPS Engine Software:

Exploit Probability

EPSS
0.10%
Percentile
26.61%

EPSS (Exploit Prediction Scoring System) scores estimate the probability that a vulnerability will be exploited in the wild within the next 30 days. The percentile shows you how this score compares to all other vulnerabilities.