{"id":"UBUNTU-CVE-2021-45098","details":"An issue was discovered in Suricata before 6.0.4. It is possible to bypass/evade any HTTP-based signature by faking an RST TCP packet with random TCP options of the md5header from the client side. After the three-way handshake, it's possible to inject an RST ACK with a random TCP md5header option. Then, the client can send an HTTP GET request with a forbidden URL. The server will ignore the RST ACK and send the response HTTP packet for the client's request. These packets will not trigger a Suricata reject action.","modified":"2025-10-24T04:50:38Z","published":"2021-12-16T05:15:00Z","upstream":["CVE-2021-45098"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-45098"},{"type":"REPORT","url":"https://forum.suricata.io/t/suricata-6-0-4-and-5-0-8-released/1942"},{"type":"REPORT","url":"https://github.com/OISF/suricata/commit/50e2b973eeec7172991bf8f544ab06fb782b97df"},{"type":"REPORT","url":"https://redmine.openinfosecfoundation.org/issues/4710"},{"type":"REPORT","url":"https://github.com/OISF/suricata/releases"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-45098"}],"affected":[{"package":{"name":"suricata","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/suricata@3.0-1?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.8-1build1","2.0.9-1","2.0.10-1","2.0.10-2","2.0.11-1","3.0-1"],"ecosystem_specific":{"binaries":[{"binary_name":"suricata","binary_version":"3.0-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-45098.json"}},{"package":{"name":"suricata","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/suricata@3.2-2ubuntu3?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.2-2ubuntu3"],"ecosystem_specific":{"binaries":[{"binary_version":"3.2-2ubuntu3","binary_name":"libhtp-0.5.23-1"},{"binary_name":"suricata","binary_version":"3.2-2ubuntu3"},{"binary_name":"suricata-hyperscan","binary_version":"3.2-2ubuntu3"},{"binary_name":"suricata-oinkmaster","binary_version":"3.2-2ubuntu3"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-45098.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"},{"type":"Ubuntu","score":"medium"}]}