Use-after-free in Snort - CVE-2026-20026
Published: January 7, 2026 / Updated: January 29, 2026
Vulnerability identifier: #VU121069
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-20026
CWE-ID: CWE-416
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to perform a denial of service attack.
The vulnerability exists due to a use-after-free error when processing DCE/RPC requests. A remote non-authenticated attacker can send a large number of DCE/RPC requests through an established connection that is inspected by Snort, trigger a use-after-free read and perform a denial of service attack against the Snort 3 Detection Engine.
Successful exploitation of the vulnerability may allow an attacker to compromise vulnerable system.
Affected software
Snort
Cisco Secure Firewall Threat Defense (FTD)
Cisco IOS XE
Cisco Secure Firewall Threat Defense (FTD)
Cisco IOS XE
How to mitigate CVE-2026-20026
Install updates from vendor's website.
Snort - update to 3.9.6.0
Cisco Secure Firewall Threat Defense (FTD) - addressed in versions 7.0.8.2-2, 7.2.10.3-1
Cisco IOS XE - update to 26.1.1
Cisco Secure Firewall Threat Defense (FTD) - addressed in versions 7.0.8.2-2, 7.2.10.3-1
Cisco IOS XE - update to 26.1.1