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Fencer Vulns
medium 5.8

CVE-2026-20067 json

Multiple Cisco Products Snort 3 TBD Denial of Service Vulnerability

published 2026-03-04 8 mo ago modified 2026-08-19 2 mo ago also EUVD-2026-9466

cvss
5.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.5%
EPSS 0.5% chance of exploitation in 30 days, percentile 44%
public exploits
0
none known

Summary

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.

Patch / fix

  • cisco snort 3.9.5.0

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
8 mo ago

Exploit prediction

0.52% chance of exploitation in the next 30 days, higher than 44% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L

Affected products

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

Classification

Weakness

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.