CVE-2026-20218
Cisco Secure Firewall Threat Defense Snort 3 Visual Basic for Applications Buffer Overflow Denial of Service Vulnerability
- Published
- Updated
- Reserved
- Assigned by
- cisco
Description
A vulnerability in the Snort 3 Visual Basic for Applications (VBA) Decompression Engine of multiple Cisco products could allow an unauthenticated, remote attacker to cause the Snort 3 Detection Engine to restart unexpectedly, resulting in a denial of service (DoS) condition. This vulnerability is due to improper range checking when Snort 3 decompresses VBA data, which is user controlled. An attacker could exploit this vulnerability by sending crafted VBA data to the Snort 3 Detection Engine of a targeted device. A successful exploit could allow the attacker to cause an overflow of stack data, which could result in a DoS condition.
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:N/A:L |
| NVDNVD · Awaiting Analysis | 3.1 | Medium5.8 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L |
- EPSS (exploitation in 30 days)
- 0.63% · top 50% of all CVEs (6 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.
Weakness
Affected products
Cisco · Cisco Open Source Snort3
- affected 3.12.2.0
- affected 3.1.2.0
- affected 3.1.3.0
- affected 3.1.4.0
- affected 3.1.5.0
- affected 3.1.6.0
- affected 3.1.7.0
- affected 3.1.8.0
- affected 3.1.9.0
- affected 3.1.10.0
- affected 3.1.12.0
- affected 3.1.13.0
- affected 3.1.14.0
- affected 3.1.15.0
- affected 3.1.16.0
- affected 3.1.17.0
- affected 3.1.18.0
- affected 3.1.19.0
- affected 3.1.20.0
- affected 3.1.21.0
- affected 3.1.22.0
- affected 3.1.23.0
- affected 3.1.24.0
- affected 3.1.25.0
- affected 3.1.27.0
- affected 3.1.28.0
- affected 3.1.29.0
- affected 3.1.30.0
- affected 3.1.31.0
- affected 3.1.32.0
- affected 3.1.36.0
- affected 3.1.38.0
- affected 3.1.39.0
- affected 3.1.40.0
- affected 3.1.41.0
- affected 3.1.42.0
- affected 3.1.43.0
- affected 3.1.45.0
- affected 3.1.47.0
- affected 3.1.48.0
- and 65 more
Cisco · Cisco Secure Firewall Threat Defense (FTD) Software
- affected 7.2.0
- affected 7.2.0.1
- affected 7.2.1
- affected 7.3.0
- affected 7.2.2
- affected 7.2.3
- affected 7.3.1
- affected 7.2.4
- affected 7.2.5
- affected 7.2.4.1
- affected 7.3.1.1
- affected 7.4.0
- affected 7.2.5.1
- affected 7.4.1
- affected 7.2.6
- affected 7.4.1.1
- affected 7.2.7
- affected 7.2.5.2
- affected 7.3.1.2
- affected 7.2.8
- affected 7.6.0
- affected 7.4.2
- affected 7.2.8.1
- affected 7.4.2.1
- affected 7.2.9
- affected 7.7.0
- affected 7.4.2.2
- affected 7.2.10
- affected 7.6.1
- affected 7.4.2.3
- affected 7.6.2
- affected 7.7.10
- affected 7.7.11
- affected 7.6.2.1
- affected 7.7.10.1
- affected 7.4.2.4
- affected 7.2.10.2
- affected 7.4.3
- affected 7.6.4
- affected 10.0.0
- and 3 more
Cisco · Cisco UTD SNORT IPS Engine Software
- affected 17.12.1a
- affected 17.12.2
- affected 17.13.1a
- affected 17.12.3
- affected 17.14.1a
- affected 17.12.4
- affected 17.12.3a
- affected 17.15.1a
- affected 17.16.1a
- affected 17.12.4a
- affected 17.15.2c
- affected 17.12.4b
- affected 17.15.2a
- affected 17.12.5
- affected 17.17.1
- affected 17.12.5a
- affected 17.15.3a
- affected 17.15.3
- affected 17.12.5b
- affected 17.12.5c
- affected 17.15.4
- affected 17.18.1
- affected 17.18.1a
- affected 17.12.6
- affected 17.15.4c
- affected 17.12.5d
- affected 17.18.2
- affected 26.1.1
- affected 17.15.5
- affected 17.15.5a
- affected 17.12.7
- affected 17.12.7a
- affected 17.12.7b
- affected 17.18.3a
- affected 17.12.8
- affected 17.15.6
- affected 17.18.4
- affected 26.1.2
What to do
Exploitation: The Cisco PSIRT is not aware of any public announcements or malicious use of the vulnerability that is described in this advisory.
References (1)
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)
- 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://trackcve.app/cve/CVE-2026-20218)Record last updated .