Cisco Snort 3: Improper privilege management in multiple Cisco products

Summary

Several Cisco products that use the Snort 3 inspection engine are affected by an improper privilege management flaw (CWE-269), fixed in a Snort 3 hardening release from October 2026. A local attacker with low privileges on an affected device could escalate privileges and gain high impact on confidentiality, integrity and availability. Cisco rates the issue 7.8 (High) and reports no workarounds, so patching is the only documented remedy.

Affected

• Open Source Snort 3
• Cisco Secure Firewall Threat Defense (FTD) Software
• Cisco Cyber Vision
• UTD Snort IPS Engine on Cisco IOS XE
• Cisco CDFW, Cisco Secure Access and Cisco Meraki MX are listed as vulnerable in the advisory, but Cisco states no customer action is required for these cloud or managed products
• Exact affected version ranges: check the Cisco advisory tables, as the full list was not verified here

Fixed in

• Open Source Snort 3: 3.12.4.0
• Secure FTD: 7.0.10, 7.2.12, 7.4.8, 7.6.6, 7.7.13, 10.0.2 and 10.1.0 for the respective trains; earlier releases must migrate
• Cyber Vision: 5.6.0; earlier releases must migrate to a fixed release
• UTD on IOS XE: Unknown (check the Cisco advisory table)

Workaround

Cisco states that there are no workarounds that address these vulnerabilities. Interim measure (own assessment, not from Cisco): restrict local access to affected devices and their administrator accounts.

Exploitation

• Cisco PSIRT is not aware of public announcements or malicious use.
• The issues were found internally by Cisco during a security review.
• CISA SSVC assessment: exploitation none, not automatable, total technical impact.
• No public proof of concept found; CISA KEV status not verified.

Our recommendation

• Inventory all Snort 3-based products (FTD, Cyber Vision, UTD on IOS XE, Open Source Snort 3) and their versions.
• Patch on-premises FTD and IOS XE devices in the next maintenance window; prioritise perimeter devices.
• Upgrade Cyber Vision releases earlier than 5.6 to 5.6.0 or later.
• Confirm the UTD fixed release in the Cisco advisory before patching IOS XE.
• Limit local and administrator access to affected devices and monitor for unusual privilege changes.
• Treat this together with the other October 2026 Snort 3 advisories, including CVE-2026-20043, as one patch project.

Public exploits iAttack code is publicly available (PoC on GitHub, Metasploit or Exploit-DB).

PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.

Research sources

• Cisco Security Advisory cisco-sa-hardening-snort3-ybgmhTQe sec.cloudapps.cisco.com
• Cisco Security Advisory (cisco.com mirror) www.cisco.com
• OpenCVE CVE-2026-20291 app.opencve.io
• Vulners Rapid7 CVE-2026-20291 vulners.com
• HOL Guard CVE-2026-20291 hol.org

Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 1 Nov 2026, 22:51.