{"id":"UBUNTU-CVE-2021-23017","details":"A security issue in nginx resolver was identified, which might allow an attacker who is able to forge UDP packets from the DNS server to cause 1-byte memory overwrite, resulting in worker process crash or potential other impact.","modified":"2026-01-30T02:03:08.207628Z","published":"2021-05-25T00:00:00Z","related":["USN-4967-1","USN-4967-2"],"upstream":["CVE-2021-23017"],"references":[{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2021-23017"},{"type":"REPORT","url":"https://www.x41-dsec.de/lab/advisories/x41-2021-002-nginx-resolver-copy/"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-4967-1"},{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-4967-2"},{"type":"REPORT","url":"https://www.cve.org/CVERecord?id=CVE-2021-23017"}],"affected":[{"package":{"name":"nginx","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/nginx@1.4.6-1ubuntu3.9+esm2?arch=source&distro=trusty/esm"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.4.6-1ubuntu3.9+esm2"}]}],"versions":["1.4.1-3ubuntu1","1.4.3-2ubuntu1","1.4.4-1ubuntu1","1.4.4-2ubuntu1","1.4.4-4ubuntu1","1.4.5-1ubuntu1","1.4.6-1ubuntu2","1.4.6-1ubuntu3","1.4.6-1ubuntu3.1","1.4.6-1ubuntu3.2","1.4.6-1ubuntu3.3","1.4.6-1ubuntu3.4","1.4.6-1ubuntu3.5","1.4.6-1ubuntu3.6","1.4.6-1ubuntu3.7","1.4.6-1ubuntu3.8","1.4.6-1ubuntu3.9","1.4.6-1ubuntu3.9+esm1"],"ecosystem_specific":{"binaries":[{"binary_name":"nginx","binary_version":"1.4.6-1ubuntu3.9+esm2"},{"binary_name":"nginx-common","binary_version":"1.4.6-1ubuntu3.9+esm2"},{"binary_name":"nginx-core","binary_version":"1.4.6-1ubuntu3.9+esm2"},{"binary_name":"nginx-extras","binary_version":"1.4.6-1ubuntu3.9+esm2"},{"binary_name":"nginx-full","binary_version":"1.4.6-1ubuntu3.9+esm2"},{"binary_name":"nginx-light","binary_version":"1.4.6-1ubuntu3.9+esm2"},{"binary_name":"nginx-naxsi","binary_version":"1.4.6-1ubuntu3.9+esm2"},{"binary_name":"nginx-naxsi-ui","binary_version":"1.4.6-1ubuntu3.9+esm2"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-23017.json"}},{"package":{"name":"nginx","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/nginx@1.10.3-0ubuntu0.16.04.5+esm1?arch=source&distro=esm-infra/xenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.10.3-0ubuntu0.16.04.5+esm1"}]}],"versions":["1.9.3-1ubuntu1","1.9.6-2ubuntu1","1.9.6-2ubuntu2","1.9.9-0ubuntu1","1.9.9-1ubuntu1","1.9.10-0ubuntu1","1.9.10-1ubuntu1","1.9.11-0ubuntu1","1.9.11-0ubuntu2","1.9.12-0ubuntu1","1.9.13-0ubuntu1","1.9.14-0ubuntu1","1.9.15-0ubuntu1","1.10.0-0ubuntu0.16.04.1","1.10.0-0ubuntu0.16.04.2","1.10.0-0ubuntu0.16.04.3","1.10.0-0ubuntu0.16.04.4","1.10.3-0ubuntu0.16.04.1","1.10.3-0ubuntu0.16.04.2","1.10.3-0ubuntu0.16.04.3","1.10.3-0ubuntu0.16.04.4","1.10.3-0ubuntu0.16.04.5"],"ecosystem_specific":{"binaries":[{"binary_name":"nginx","binary_version":"1.10.3-0ubuntu0.16.04.5+esm1"},{"binary_name":"nginx-common","binary_version":"1.10.3-0ubuntu0.16.04.5+esm1"},{"binary_name":"nginx-core","binary_version":"1.10.3-0ubuntu0.16.04.5+esm1"},{"binary_name":"nginx-extras","binary_version":"1.10.3-0ubuntu0.16.04.5+esm1"},{"binary_name":"nginx-full","binary_version":"1.10.3-0ubuntu0.16.04.5+esm1"},{"binary_name":"nginx-light","binary_version":"1.10.3-0ubuntu0.16.04.5+esm1"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-23017.json"}},{"package":{"name":"nginx","ecosystem":"Ubuntu:18.04:LTS","purl":"pkg:deb/ubuntu/nginx@1.14.0-0ubuntu1.9?arch=source&distro=bionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.14.0-0ubuntu1.9"}]}],"versions":["1.12.1-0ubuntu2","1.13.6-2ubuntu1","1.13.6-2ubuntu2","1.13.10-1ubuntu1","1.13.12-0ubuntu1","1.14.0-0ubuntu1","1.14.0-0ubuntu1.1","1.14.0-0ubuntu1.2","1.14.0-0ubuntu1.3","1.14.0-0ubuntu1.4","1.14.0-0ubuntu1.5","1.14.0-0ubuntu1.6","1.14.0-0ubuntu1.7"],"ecosystem_specific":{"binaries":[{"binary_name":"libnginx-mod-http-auth-pam","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-cache-purge","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-dav-ext","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-echo","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-fancyindex","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-geoip","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-headers-more-filter","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-image-filter","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-lua","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-ndk","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-perl","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-subs-filter","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-uploadprogress","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-upstream-fair","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-http-xslt-filter","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-mail","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-nchan","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-rtmp","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"libnginx-mod-stream","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"nginx","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"nginx-common","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"nginx-core","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"nginx-extras","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"nginx-full","binary_version":"1.14.0-0ubuntu1.9"},{"binary_name":"nginx-light","binary_version":"1.14.0-0ubuntu1.9"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-23017.json"}},{"package":{"name":"nginx","ecosystem":"Ubuntu:20.04:LTS","purl":"pkg:deb/ubuntu/nginx@1.18.0-0ubuntu1.2?arch=source&distro=focal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.18.0-0ubuntu1.2"}]}],"versions":["1.16.1-0ubuntu2","1.16.1-0ubuntu3","1.17.5-0ubuntu1","1.17.6-0ubuntu1","1.17.7-0ubuntu1","1.17.8-0ubuntu1","1.17.8-0ubuntu2","1.17.8-0ubuntu3","1.17.9-0ubuntu1","1.17.9-0ubuntu2","1.17.9-0ubuntu3","1.17.10-0ubuntu1","1.18.0-0ubuntu1"],"ecosystem_specific":{"binaries":[{"binary_name":"libnginx-mod-http-auth-pam","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-cache-purge","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-dav-ext","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-echo","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-fancyindex","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-geoip","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-geoip2","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-headers-more-filter","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-image-filter","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-lua","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-ndk","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-perl","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-subs-filter","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-uploadprogress","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-upstream-fair","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-http-xslt-filter","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-mail","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-nchan","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-rtmp","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"libnginx-mod-stream","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"nginx","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"nginx-common","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"nginx-core","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"nginx-extras","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"nginx-full","binary_version":"1.18.0-0ubuntu1.2"},{"binary_name":"nginx-light","binary_version":"1.18.0-0ubuntu1.2"}],"availability":"No subscription required"},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/cve/2021/UBUNTU-CVE-2021-23017.json"}}],"schema_version":"1.7.3","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:L"},{"type":"Ubuntu","score":"medium"}]}