{"id":"UBUNTU-CVE-2021-1236","details":"Multiple Cisco products are affected by a vulnerability in the Snort application detection engine that could allow an unauthenticated, remote attacker to bypass the configured policies on an affected system. The vulnerability is due to a flaw in the detection algorithm. An attacker could exploit this vulnerability by sending crafted packets that would flow through an affected system. A successful exploit could allow the attacker to bypass the configured policies and deliver a malicious payload to the protected network.","modified":"2025-10-24T04:49:08Z","published":"2021-01-13T22:15:00Z","upstream":["CVE-2021-1236"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-1236"},{"type":"REPORT","url":"https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-snort-app-bypass-cSBYCATq"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-1236"}],"affected":[{"package":{"name":"snort","ecosystem":"Ubuntu:14.04:LTS","purl":"pkg:deb/ubuntu/snort@2.9.6.0-0ubuntu1?arch=source&distro=trusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.9.2.2-3","2.9.5.3-3","2.9.6.0-0ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_version":"2.9.6.0-0ubuntu1","binary_name":"snort"},{"binary_version":"2.9.6.0-0ubuntu1","binary_name":"snort-common"},{"binary_name":"snort-common-libraries","binary_version":"2.9.6.0-0ubuntu1"},{"binary_name":"snort-rules-default","binary_version":"2.9.6.0-0ubuntu1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-1236.json"}},{"package":{"name":"snort","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/snort@2.9.7.0-5?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.9.7.0-5"],"ecosystem_specific":{"binaries":[{"binary_name":"snort","binary_version":"2.9.7.0-5"},{"binary_name":"snort-common","binary_version":"2.9.7.0-5"},{"binary_name":"snort-common-libraries","binary_version":"2.9.7.0-5"},{"binary_name":"snort-rules-default","binary_version":"2.9.7.0-5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-1236.json"}},{"package":{"name":"snort","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/snort@2.9.7.0-5build1?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.9.7.0-5","2.9.7.0-5build1"],"ecosystem_specific":{"binaries":[{"binary_name":"snort","binary_version":"2.9.7.0-5build1"},{"binary_name":"snort-common","binary_version":"2.9.7.0-5build1"},{"binary_name":"snort-common-libraries","binary_version":"2.9.7.0-5build1"},{"binary_name":"snort-rules-default","binary_version":"2.9.7.0-5build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-1236.json"}},{"package":{"name":"snort","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/snort@2.9.7.0-5build1?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.9.7.0-5build1"],"ecosystem_specific":{"binaries":[{"binary_name":"snort","binary_version":"2.9.7.0-5build1"},{"binary_name":"snort-common","binary_version":"2.9.7.0-5build1"},{"binary_name":"snort-common-libraries","binary_version":"2.9.7.0-5build1"},{"binary_name":"snort-rules-default","binary_version":"2.9.7.0-5build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-1236.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N"},{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N"},{"type":"Ubuntu","score":"medium"}]}