{"id":"UBUNTU-CVE-2026-40211","details":"An attacker can send crafted DNS over HTTP/3 queries, triggering an exception that prevents some buffer from being freed right away. The buffer will be freed at the end of the QUIC connection, but on some setups it might be possible to open enough concurrent DoH3 streams to trigger an out-of-memory condition, resulting in a denial of service.","modified":"2026-06-29T23:15:39.228814894Z","published":"2026-06-25T13:16:00Z","upstream":["CVE-2026-40211"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-40211"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2026-40211"},{"type":"REPORT","url":"https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html#cve-2026-40211-denial-of-service-via-crafted-doh3-queries"}],"affected":[{"package":{"name":"dnsdist","ecosystem":"Ubuntu:16.04:LTS","purl":"pkg:deb/ubuntu/dnsdist?arch=source&distro=xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.0~alpha2-1"],"ecosystem_specific":{"binaries":[{"binary_name":"dnsdist","binary_version":"1.0.0~alpha2-1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40211.json"}},{"package":{"name":"dnsdist","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/dnsdist?arch=source&distro=esm-apps%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.2.0-1","1.2.0-3","1.2.1-1","1.2.1-1build1","1.2.1-1ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"dnsdist","binary_version":"1.2.1-1ubuntu0.1~esm1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40211.json"}},{"package":{"name":"dnsdist","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/dnsdist?arch=source&distro=esm-apps%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.4.0~rc3-1","1.4.0-1","1.4.0-1build1","1.4.0-1build2","1.4.0-1ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.4.0-1ubuntu0.1~esm1","binary_name":"dnsdist"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40211.json"}},{"package":{"name":"dnsdist","ecosystem":"Ubuntu:Pro:22.04:LTS","purl":"pkg:deb/ubuntu/dnsdist?arch=source&distro=esm-apps%2Fjammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.5.1-3build2","1.6.1-1build1","1.6.1-1ubuntu0.1~esm1","1.6.1-1ubuntu0.1~esm2"],"ecosystem_specific":{"binaries":[{"binary_name":"dnsdist","binary_version":"1.6.1-1ubuntu0.1~esm2"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40211.json"}},{"package":{"name":"dnsdist","ecosystem":"Ubuntu:Pro:24.04:LTS","purl":"pkg:deb/ubuntu/dnsdist?arch=source&distro=esm-apps%2Fnoble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.8.0-1","1.8.2-1","1.8.2-2","1.8.2-3","1.8.3-1","1.8.3-2","1.8.3-2build1","1.8.3-2build2","1.8.3-2ubuntu0.1~esm1"],"ecosystem_specific":{"binaries":[{"binary_version":"1.8.3-2ubuntu0.1~esm1","binary_name":"dnsdist"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40211.json"}},{"package":{"name":"dnsdist","ecosystem":"Ubuntu:25.10","purl":"pkg:deb/ubuntu/dnsdist?arch=source&distro=questing"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.9.8-1","1.9.10-1","1.9.10-1ubuntu0.1"],"ecosystem_specific":{"binaries":[{"binary_name":"dnsdist","binary_version":"1.9.10-1ubuntu0.1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40211.json"}},{"package":{"name":"dnsdist","ecosystem":"Ubuntu:26.04:LTS","purl":"pkg:deb/ubuntu/dnsdist?arch=source&distro=resolute"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.9.10-1","2.0.1-1","2.0.2-1","2.0.2-1build1"],"ecosystem_specific":{"binaries":[{"binary_name":"dnsdist","binary_version":"2.0.2-1build1"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2026/UBUNTU-CVE-2026-40211.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L"},{"type":"Ubuntu","score":"medium"}]}