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Fencer Intel
medium 5.8

CVE-2026-20290 json

Cisco Secure Firewall Threat Defense Software Snort 2 SSL/TLS Denial of Service Vulnerability

published last mo. modified last mo. also EUVD-2026-81150

cvss
5.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 23%
public exploits
0
none known

Summary

A vulnerability in SSL/TLS certificate parsing in the Snort 2 Detection Engine of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause the Snort 2 Detection Engine to restart.

This vulnerability is due to incomplete validation of the SSL certificate. An attacker could exploit this vulnerability by sending a crafted SSL connection setup request to be parsed by Snort 2. A successful exploit could allow the attacker to cause the Snort 2 Detection Engine to restart unexpectedly, resulting in a denial of service (DoS) condition.

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CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
partial
Assessed
last mo.

Exploit prediction

0.31% chance of exploitation in the next 30 days, higher than 23% of all scored CVEs (FIRST EPSS, 2026-11-09).

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 Secure Firewall Threat Defense (FTD) Software

Classification

Weakness
  • CWE-805 Buffer Access with Incorrect Length Value

References

Sources

Fencer Intel 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.