CVE-2026-20066: Multiple Cisco Products Snort 3 TBD Denial of Service Vulnerability
Cisco · Cisco Secure Firewall Threat Defense (FTD) Software
Affected: Cisco Secure Firewall Threat Defense (FTD) Software · Exploitation: unlikely (under 1%)
Not in CyberSIXT coverage yet: no article names this CVE. This page shows the public record.
Higher than 44% of scored CVEs
DescriptionCVE.org
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 an error in the JSTokenizer normalization logic when the HTTP inspection normalizes JavaScript. An attacker could exploit this vulnerability by sending crafted HTTP packets through an established connection that is parsed by Snort 3. A successful exploit could allow the attacker to cause a DoS condition when the Snort 3 Detection Engine restarts unexpectedly. JSTokenizer is not enabled by default.
Affected products2
From the CVE record. A product or version that is not listed is unknown, not unaffected.
- Cisco · Cisco Secure Firewall Threat Defense (FTD) Software7.4.0; 7.4.1; 7.4.1.1; 7.6.0; 7.4.2; 7.4.2.1 and 10 more
- Cisco · Cisco UTD SNORT IPS Engine Software17.3.1a; 17.2.1r; 17.3.2; 17.4.1a; 17.5.1; 17.3.3 and 65 more
On the Atlas
Every published CVE is on the CyberSIXT Atlas, grouped by weakness, vendor and month.
- Exploitation
- Unlikely (under 1%). EPSS under 1%, or no score yet.
- CISA KEV
- Not listed
- Public check
- No public nuclei template
- Vendor
- Cisco
- Published
- March 2026
CoverageNo articles yet
No CyberSIXT article names CVE-2026-20066 yet, so there is no coverage timeline, action brief or change log for it. Everything on this page comes from the public CVE record, CISA KEV, EPSS and the nuclei template index. Search the archive or see the CVEs in the news.