Out-of-bounds read in Snort - CVE-2026-20027
Published: January 7, 2026 / Updated: January 29, 2026
Vulnerability identifier: #VU121070
CSH Severity: Medium
CVSS v4: 8.7 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-20027
CWE-ID: CWE-125
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to gain access to potentially sensitive information.
The vulnerability exists due to a boundary condition when handling DCE/RPC requests. A remote attacker can send a large number of DCE/RPC requests through an established connection that is inspected by Snort 3 and obtain sensitive information in the Snort 3 data stream.
Affected software
Snort
Cisco Firewall Threat Defense (FTD)
Cisco IOS XE
Cisco Firewall Threat Defense (FTD)
Cisco IOS XE
How to mitigate CVE-2026-20027
Install updates from vendor's website.
Snort - update to 3.9.6.0
Cisco 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 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