CVE-2026-20007
Cisco Secure Firewall Threat Defense Software Snort Deep Inspection Bypass Vulnerability
- 5.8MediumCVSS base score
- 0.27%Exploitation in 30 daysEPSS · top 81% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
A vulnerability in the Snort 2 and Snort 3 deep packet inspection of Cisco Secure Firewall Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to bypass configured Snort rules and allow traffic onto the network that should have been dropped. This vulnerability is due to a logic error in the integration of the Snort Engine rules with Cisco Secure FTD Software that could allow different Snort rules to be hit when deep inspection of the packet is performed for the inner and outer connections. An attacker could exploit this vulnerability by sending crafted traffic to a targeted device that would hit configured Snort rules. A successful exploit could allow the attacker to send traffic to a network where it should have been denied.
Timeline
ID reserved
By cisco
- 5 months later
· 5 months later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| ciscoCNA (assigner) | 3.1 | Medium5.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
| NVDNVD · Analyzed | 3.1 | Medium5.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:L/A:N |
- EPSS (exploitation in 30 days)
- 0.27% · top 81% of all CVEs (10 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 5.8.
Affected products
Cisco · Cisco Secure Firewall Threat Defense (FTD) Software
- affected 6.4.0.1
- affected 6.4.0.2
- affected 6.4.0.5
- affected 6.4.0
- affected 6.4.0.3
- affected 6.4.0.4
- affected 6.4.0.6
- affected 6.4.0.7
- affected 6.4.0.8
- affected 6.4.0.9
- affected 6.4.0.10
- affected 6.4.0.11
- affected 6.4.0.12
- affected 7.0.0
- affected 7.0.0.1
- affected 7.0.1
- affected 7.1.0
- affected 6.4.0.13
- affected 7.0.1.1
- affected 6.4.0.14
- affected 7.1.0.1
- affected 7.0.2
- affected 6.4.0.15
- affected 7.2.0
- affected 7.0.2.1
- affected 7.0.3
- affected 7.1.0.2
- affected 7.2.0.1
- affected 7.0.4
- affected 7.2.1
- affected 7.0.5
- affected 6.4.0.16
- affected 7.3.0
- affected 7.2.2
- affected 7.2.3
- affected 7.3.1
- affected 7.1.0.3
- affected 7.2.4
- affected 7.0.6
- affected 7.2.5
- and 33 more
What to do
Exploitation: The Cisco Product Security Incident Response Team (PSIRT) is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-9454 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-20007)Record last updated .