{"id":"CVE-2026-40209","aliases":["DEBIAN-CVE-2026-40209","EUVD-2026-39348","GHSA-c5m7-ppm5-wp5g","SUSE-SU-2026:23123-1","SUSE-SU-2026:23146-1","UBUNTU-CVE-2026-40209","openSUSE-SU-2026:11411-1","openSUSE-SU-2026:21533-1"],"status":"published","title":"Denial of service via IXFR queries","description":"An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.","severity":{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.007,"percentile":0.53515,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-772"],"published":"2026-06-25T12:23:05Z","modified":"2026-10-28T10:49:42Z","fixes":[{"ecosystem":"Debian:13","package":"dnsdist","fixed_in":["1.9.15-0+deb13u1"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"dnsdist","fixed_in":["2.1.0-1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Debian:12","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.7.3-2","1.8.0-1","1.8.1-1","1.8.2-1","1.8.2-2","1.8.2-3","1.8.3-1","1.8.3-2","1.8.3-3","1.9.10-1","1.9.3-1","1.9.4-1","1.9.5-1","1.9.6-1","1.9.8-1","1.9.9-1","2.0.0-1","2.0.0-2","2.0.0-3","2.0.0-4","2.0.0-5","2.0.0-6","2.0.0~rc1-1","2.0.0~rc1-2","2.0.0~rc2-1","2.0.1-1","2.0.2-1","2.0.3-1","2.0.4-1","2.0.5-1","2.0.5-2","2.0.5-3","2.0.6-1","2.1.0-1","2.1.0-2","2.1.1-1","2.1.2-1","2.1.3-1"]},{"source":"osv","ecosystem":"Debian:13","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.15-0+deb13u1"}]}],"versions":["1.9.10-1","1.9.10-1+deb13u1","1.9.14-0+deb13u1"]},{"source":"osv","ecosystem":"Debian:14","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.1.0-1"}]}],"versions":["1.9.10-1","2.0.0-1","2.0.0-2","2.0.0-3","2.0.0-4","2.0.0-5","2.0.0-6","2.0.0~rc1-1","2.0.0~rc1-2","2.0.0~rc2-1","2.0.1-1","2.0.2-1","2.0.3-1","2.0.4-1","2.0.5-1","2.0.5-2","2.0.5-3","2.0.6-1"]},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server 16.0","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.15-160000.1.1"}]}],"bundled":7},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server for SAP applications 16.0","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.15-160000.1.1"}]}],"bundled":7},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server 16.0","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.15-160000.1.1"}]}],"bundled":7},{"source":"osv","ecosystem":"SUSE:Linux Enterprise Server for SAP applications 16.0","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.15-160000.1.1"}]}],"bundled":7},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.0.0~alpha2-1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"dnsdist","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"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"dnsdist","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"]},{"source":"osv","ecosystem":"Ubuntu:Pro:22.04:LTS","package":"dnsdist","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"]},{"source":"osv","ecosystem":"Ubuntu:Pro:24.04:LTS","package":"dnsdist","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"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.9.8-1","1.9.10-1","1.9.10-1ubuntu0.1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.0.2-1build1","2.0.5-2ubuntu1","2.0.5-2ubuntu3"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.9.10-1","2.0.1-1","2.0.2-1","2.0.2-1build1"]},{"source":"osv","ecosystem":"openSUSE:Tumbleweed","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.7-1.1"}]}],"bundled":7},{"source":"osv","ecosystem":"openSUSE:Leap 16.0","package":"dnsdist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.15-160000.1.1"}]}],"bundled":7}],"products":[{"vendor":"powerdns","product":"dnsdist"}],"references":[{"url":"https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html","tags":["advisory"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40209","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-c5m7-ppm5-wp5g"},{"url":"https://repo.powerdns.com/","tags":["web"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/40xxx/CVE-2026-40209.json","tags":["advisory"]},{"url":"https://github.com/PowerDNS/pdns","tags":["package"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-40209","tags":["advisory"]},{"url":"https://www.suse.com/support/update/announcement/2026/suse-su-202623123-1/","tags":["advisory"]},{"url":"https://bugzilla.suse.com/1269201","tags":["report"]},{"url":"https://bugzilla.suse.com/1269202","tags":["report"]},{"url":"https://bugzilla.suse.com/1269203","tags":["report"]},{"url":"https://bugzilla.suse.com/1269204","tags":["report"]},{"url":"https://bugzilla.suse.com/1269205","tags":["report"]},{"url":"https://bugzilla.suse.com/1269206","tags":["report"]},{"url":"https://bugzilla.suse.com/1269207","tags":["report"]},{"url":"https://www.suse.com/security/cve/CVE-2026-40011","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-40208","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-40209","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-40210","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-40211","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-42004","tags":["web"]},{"url":"https://www.suse.com/security/cve/CVE-2026-42005","tags":["web"]},{"url":"https://www.suse.com/support/update/announcement/2026/suse-su-202623146-1/","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-40209","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-40209","tags":["report"]},{"url":"https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-09.html#cve-2026-40209-denial-of-service-via-ixfr-queries","tags":["report"]},{"url":"","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-40209","title":"Denial of service via IXFR queries","description":"An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.","status":"published","published":"2026-06-25T12:23:05.694Z","modified":"2026-06-25T13:56:22.793Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"cna"}],"cwes":["CWE-772"],"updated_at":"2026-11-02T13:43:11.445168Z"}],"euvd":[{"id":"EUVD-2026-39348","description":"An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.","status":"published","published":"2026-06-25T12:23:05Z","modified":"2026-06-25T13:56:22Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T18:20:29.213001Z"}],"ghsa":[{"id":"GHSA-c5m7-ppm5-wp5g","title":"An attacker might be able to cause outgoing TCP connections to backend to be stuck until a...","description":"An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.","status":"published","published":"2026-06-25T15:31:59Z","modified":"2026-06-25T15:32:09Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"cwes":["CWE-772"],"updated_at":"2026-11-02T15:08:58.724463Z"}],"nvd":[{"id":"CVE-2026-40209","description":"An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.","status":"published","published":"2026-06-25T13:16:39.527Z","modified":"2026-10-25T23:10:00.167Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium","assessor":"secondary"}],"cwes":["CWE-772"],"updated_at":"2026-11-02T14:12:26.045561Z"}],"osv":[{"id":"CVE-2026-40209","title":"Denial of service via IXFR queries","description":"An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.","status":"published","published":"2026-06-25T12:23:05.694Z","modified":"2026-10-28T10:49:42.984860024Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:45:03.424067Z"},{"id":"DEBIAN-CVE-2026-40209","description":"An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.","status":"published","published":"2026-06-25T13:16:39.527Z","modified":"2026-10-26T12:02:57.364982391Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T15:45:54.892385Z"},{"id":"UBUNTU-CVE-2026-40209","description":"An attacker might be able to cause outgoing TCP connections to backend to be stuck until a timeout occurs instead of being released immediately, by sending IXFR queries. This could be used to cause a denial of service if there is a limit to the number of concurrent connections to this backend, or if the process runs out of file descriptors.","status":"published","published":"2026-06-25T13:16:00Z","modified":"2026-10-17T13:00:03.531790923Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L","level":"medium"}],"updated_at":"2026-11-02T16:56:16.686388Z"},{"id":"openSUSE-SU-2026:11411-1","title":"dnsdist-2.0.7-1.1 on GA media","description":"These are all security issues fixed in the dnsdist-2.0.7-1.1 package on the GA media of openSUSE Tumbleweed.","status":"published","published":"2026-07-31T00:00:00Z","modified":"2026-08-01T09:45:06.06000202Z","updated_at":"2026-11-02T16:58:39.516824Z"},{"id":"openSUSE-SU-2026:21533-1","title":"Security update for dnsdist","description":"This update for dnsdist fixes the following issues:\n\nUpdate to 1.9.15.\n\nChanges for dnsdist:\n\n- https://www.dnsdist.org/changelog.html#change-1.9.15\n- https://www.dnsdist.org/changelog.html#change-1.9.14\n\nSecurity issues fixed:\n\n- CVE-2026-40011: invalid output produced in the prometheus endpoint when a large number of crafted DNS queries are sent\n  (bsc#1269204).\n- CVE-2026-40208: processing of DoH3 queries can be delayed via DoH3 GET queries with an invalid DATA frames\n  (bsc#1269207).\n- CVE-2026-40209: outgoing TCP connections to backend can get stuck until a timeout occurs when specially crafted IXFR\n  queries are sent (bsc#1269206).\n- CVE-2026-40210: out-of-bounds read when `SetMacAddrAction` is used can lead to uninitialized memory being sent over\n  the network or a crash (bsc#1269205).\n- CVE-2026-40211: crafted DNS over HTTP/3 queries can trigger an exception that prevents memory from being freed and can\n  lead to an OOM condition (bsc#1269203).\n- CVE-2026-42004: crafted EDNS OPT record will be ignored by filtering rules, but will be rewritten as a valid OPT\n  record when EDNS Client Subnet is inserted (bsc#1269202).\n- CVE-2026-42005: crafted web request can cause unlimited memory allocation in the internal web server and lead to a DoS\n  (bsc#1269201).\n","status":"published","published":"2026-08-05T09:13:07Z","modified":"2026-08-06T18:23:57.734710349Z","updated_at":"2026-11-02T16:58:41.885092Z"},{"id":"SUSE-SU-2026:23123-1","title":"Security update for dnsdist","description":"This update for dnsdist fixes the following issues:\n\nUpdate to 1.9.15.\n\nChanges for dnsdist:\n\n- https://www.dnsdist.org/changelog.html#change-1.9.15\n- https://www.dnsdist.org/changelog.html#change-1.9.14\n\nSecurity issues fixed:\n\n- CVE-2026-40011: invalid output produced in the prometheus endpoint when a large number of crafted DNS queries are sent\n  (bsc#1269204).\n- CVE-2026-40208: processing of DoH3 queries can be delayed via DoH3 GET queries with an invalid DATA frames\n  (bsc#1269207).\n- CVE-2026-40209: outgoing TCP connections to backend can get stuck until a timeout occurs when specially crafted IXFR\n  queries are sent (bsc#1269206).\n- CVE-2026-40210: out-of-bounds read when `SetMacAddrAction` is used can lead to uninitialized memory being sent over\n  the network or a crash (bsc#1269205).\n- CVE-2026-40211: crafted DNS over HTTP/3 queries can trigger an exception that prevents memory from being freed and can\n  lead to an OOM condition (bsc#1269203).\n- CVE-2026-42004: crafted EDNS OPT record will be ignored by filtering rules, but will be rewritten as a valid OPT\n  record when EDNS Client Subnet is inserted (bsc#1269202).\n- CVE-2026-42005: crafted web request can cause unlimited memory allocation in the internal web server and lead to a DoS\n  (bsc#1269201).\n","status":"published","published":"2026-08-05T09:14:01Z","modified":"2026-08-14T18:23:39.882232948Z","updated_at":"2026-11-02T15:54:03.503431Z"},{"id":"SUSE-SU-2026:23146-1","title":"Security update for dnsdist","description":"This update for dnsdist fixes the following issues:\n\nUpdate to 1.9.15.\n\nChanges for dnsdist:\n\n- https://www.dnsdist.org/changelog.html#change-1.9.15\n- https://www.dnsdist.org/changelog.html#change-1.9.14\n\nSecurity issues fixed:\n\n- CVE-2026-40011: invalid output produced in the prometheus endpoint when a large number of crafted DNS queries are sent\n  (bsc#1269204).\n- CVE-2026-40208: processing of DoH3 queries can be delayed via DoH3 GET queries with an invalid DATA frames\n  (bsc#1269207).\n- CVE-2026-40209: outgoing TCP connections to backend can get stuck until a timeout occurs when specially crafted IXFR\n  queries are sent (bsc#1269206).\n- CVE-2026-40210: out-of-bounds read when `SetMacAddrAction` is used can lead to uninitialized memory being sent over\n  the network or a crash (bsc#1269205).\n- CVE-2026-40211: crafted DNS over HTTP/3 queries can trigger an exception that prevents memory from being freed and can\n  lead to an OOM condition (bsc#1269203).\n- CVE-2026-42004: crafted EDNS OPT record will be ignored by filtering rules, but will be rewritten as a valid OPT\n  record when EDNS Client Subnet is inserted (bsc#1269202).\n- CVE-2026-42005: crafted web request can cause unlimited memory allocation in the internal web server and lead to a DoS\n  (bsc#1269201).\n","status":"published","published":"2026-08-05T09:14:01Z","modified":"2026-08-14T18:23:41.283401919Z","updated_at":"2026-11-02T15:54:03.503431Z"}]}}