{"id":"CVE-2021-3593","url":"https://www.cyber-defence.io/tools/cve/CVE-2021-3593","generatedAt":"2026-10-27T17:45:13.992Z","title":"This issue may lead to out-of-bounds read access or indirect host memory disclosure to the guest.","description":"An invalid pointer initialization issue was found in the SLiRP networking implementation of QEMU. The flaw exists in the udp6_input() function and could occur while processing a udp packet that is smaller than the size of the 'udphdr' structure. This issue may lead to out-of-bounds read access or indirect host memory disclosure to the guest. The highest threat from this vulnerability is to data confidentiality. This flaw affects libslirp versions prior to 4.6.0.","published":"2021-06-15T21:15:10.000Z","lastModified":"2026-06-17T04:05:24.000Z","status":"Modified","sourceIdentifier":"secalert@redhat.com","cvss":{"version":"3.1","score":3.8,"severity":"LOW","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:N/A:N"},"cwe":["CWE-824"],"affected":["libslirp project/libslirp","redhat/enterprise linux","fedoraproject/fedora","debian/debian linux"],"epss":{"score":0.00326,"percentile":0.25485,"date":"2026-10-26","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"low","text":"Lower severity and a low EPSS score (0.33%). Track it; it rarely justifies an emergency change on its own."},"changes":[],"references":[{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=1970487","tags":["Issue Tracking","Patch","Third Party Advisory"],"source":"secalert@redhat.com"},{"url":"https://lists.debian.org/debian-lts-announce/2022/04/msg00002.html","tags":["Mailing List","Third Party Advisory"],"source":"secalert@redhat.com"},{"url":"https://lists.debian.org/debian-lts-announce/2023/03/msg00013.html","source":"secalert@redhat.com"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GCKWZWY64EHTOQMLVLTSZ4AA27EWRJMH/","source":"secalert@redhat.com"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SGPQZFVJCFGDSISFXPCQTTBBD7QZLJKI/","source":"secalert@redhat.com"},{"url":"https://security.gentoo.org/glsa/202107-44","tags":["Third Party Advisory"],"source":"secalert@redhat.com"},{"url":"https://security.netapp.com/advisory/ntap-20210805-0004/","tags":["Third Party Advisory"],"source":"secalert@redhat.com"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=1970487","tags":["Issue Tracking","Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2022/04/msg00002.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2023/03/msg00013.html","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/GCKWZWY64EHTOQMLVLTSZ4AA27EWRJMH/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SGPQZFVJCFGDSISFXPCQTTBBD7QZLJKI/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/202107-44","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20210805-0004/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2021-3593","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}