Cisco has disclosed multiple critical vulnerabilities in its Snort 3 Detection Engine that could allow unauthenticated remote attackers to leak sensitive data or disrupt services across multiple enterprise security products.
The vulnerabilities, identified as CVE-2026-20026 and CVE-2026-20027, stem from improper buffer handling in Distributed Computing Environment/Remote Procedure Call (DCE/RPC) request processing and affect numerous Cisco security appliances, firewalls, and network devices.
According to Cisco’s security advisory cisco-sa-snort3-dcerpc-vulns-J9HNF4tH published January 7, 2026, the flaws enable attackers to trigger buffer use-after-free and out-of-bounds read conditions by sending large numbers of crafted DCE/RPC requests through inspected connections.
The vulnerabilities carry a Medium severity rating with a CVSS base score of 5.8, indicating moderate risk to affected infrastructure.
The impact extends across Cisco’s entire security product portfolio. Open Source Snort 3, Cisco Secure Firewall Threat Defense (FTD) Software, Cisco IOS XE Software with Unified Threat Defense
(UTD), Multiple Cisco Meraki edge appliances are confirmed vulnerable. Enterprise organizations running these platforms face potential data exfiltration and denial-of-service conditions that could interrupt critical packet inspection capabilities.
Notably, Cisco has confirmed that Snort 2 and several other products, including ASA Software, Management Center, and Umbrella solutions, remain unaffected.
The vulnerability timeline is particularly concerning for enterprises. Cisco has released software updates and hotfixes for affected products, but the vulnerability response has spanned several months. Open Source Snort 3 requires version 3.9.6.0 or later.
Cisco Secure FTD Software releases 7.0 and 7.2 have received hot fixes, while Cisco IOS XE Software with UTD is receiving patches through February 2026.
For Meraki products, fixes are planned for February 2026, leaving a significant window of exposure.
Cisco emphasized that no workarounds are available to mitigate these vulnerabilities, making immediate patching essential.
Organizations should prioritize identifying systems running Snort 3 configurations, particularly on FTD deployments where Snort 3 runs by default on new installations of release 7.0.0 and later.
The PSIRT reports no active exploitation or public disclosures of these vulnerabilities at this time, but the lack of workarounds demands urgent action.
Security teams must validate their environments with Cisco’s Software Checker tool to assess exposure levels and systematically deploy available patches.
Organizations with legacy FTD systems running Snort 2 have lower immediate risk, though comprehensive vulnerability management remains essential across all security infrastructure components.
| CVE ID | Product Category | CVSS Base Score | Attack Vector | Primary Impact | Fixed Release |
|---|---|---|---|---|---|
| CVE-2026-20026 | Snort 3 / FTD / IOS XE UTD / Meraki | 5.8 | Network/Unauthenticated | Denial of Service, Engine Restart | Snort 3.9.6.0+ |
| CVE-2026-20027 | Snort 3 / FTD / IOS XE UTD / Meraki | 5.3 | Network/Unauthenticated | Information Disclosure | Snort 3.9.6.0+ |
Follow us on Google News , LinkedIn and X to Get More Instant Updates. Set Cyber Press as a Preferred Source in Google.
%20(1).webp?fit=1600,900&ssl=1&description=According to Cisco's security advisory cisco-sa-snort3-dcerpc-vulns-J9HNF4tH published January 7, 2026, the flaws enable attackers to trigger buffer use-after-free){kind=link}