Advisory Details

January 28th, 2026

Cisco Snort _bnfa_search_csparse_nfa Out-Of-Bounds Read Information Disclosure Vulnerability

CVE ID	CVE-2026-20027
CVSS SCORE	5.3, AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
AFFECTED VENDORS	Cisco
AFFECTED PRODUCTS	Snort
VULNERABILITY DETAILS	This vulnerability allows remote attackers to disclose sensitive information on affected installations of Cisco Snort. Authentication is not required to exploit this vulnerability. The specific flaw exists within the _bnfa_search_csparse_nfa method. The issue results from the lack of proper validation of user-supplied data, which can result in a read past the end of an allocated buffer. An attacker can leverage this in conjunction with other vulnerabilities to execute arbitrary code in the context of the service account.
ADDITIONAL DETAILS	Cisco has issued an update to correct this vulnerability. More details can be found at: https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort3-dcerpc-vulns-J9HNF4tH
DISCLOSURE TIMELINE	2025-08-12 - Vulnerability reported to vendor 2026-01-28 - Coordinated public release of advisory 2026-01-28 - Advisory Updated
CREDIT	Guy Lederfein of Trend Research

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