{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-1519","assignerOrgId":"404fd4d2-a609-4245-b543-2c944a302a22","state":"PUBLISHED","assignerShortName":"isc","dateReserved":"2026-01-28T09:54:49.514Z","datePublished":"2026-03-25T13:25:19.802Z","dateUpdated":"2026-04-13T09:35:57.526Z"},"containers":{"cna":{"providerMetadata":{"orgId":"404fd4d2-a609-4245-b543-2c944a302a22","shortName":"isc","dateUpdated":"2026-03-25T13:25:19.802Z"},"title":"Excessive NSEC3 iterations cause high CPU load during insecure delegation validation","datePublic":"2026-03-25T00:00:00.000Z","affected":[{"vendor":"ISC","product":"BIND 9","versions":[{"version":"9.11.0","lessThanOrEqual":"9.16.50","status":"affected","versionType":"custom"},{"version":"9.18.0","lessThanOrEqual":"9.18.46","status":"affected","versionType":"custom"},{"version":"9.20.0","lessThanOrEqual":"9.20.20","status":"affected","versionType":"custom"},{"version":"9.21.0","lessThanOrEqual":"9.21.19","status":"affected","versionType":"custom"},{"version":"9.11.3-S1","lessThanOrEqual":"9.16.50-S1","status":"affected","versionType":"custom"},{"version":"9.18.11-S1","lessThanOrEqual":"9.18.46-S1","status":"affected","versionType":"custom"},{"version":"9.20.9-S1","lessThanOrEqual":"9.20.20-S1","status":"affected","versionType":"custom"}],"defaultStatus":"unaffected"}],"cpeApplicability":[{"nodes":[{"operator":"OR","cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*","versionStartIncluding":"9.11.0","versionEndIncluding":"9.16.50"},{"vulnerable":true,"criteria":"cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*","versionStartIncluding":"9.18.0","versionEndIncluding":"9.18.46"},{"vulnerable":true,"criteria":"cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*","versionStartIncluding":"9.20.0","versionEndIncluding":"9.20.20"},{"vulnerable":true,"criteria":"cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*","versionStartIncluding":"9.21.0","versionEndIncluding":"9.21.19"},{"vulnerable":true,"criteria":"cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*","versionStartIncluding":"9.11.3-S1","versionEndIncluding":"9.16.50-S1"},{"vulnerable":true,"criteria":"cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*","versionStartIncluding":"9.18.11-S1","versionEndIncluding":"9.18.46-S1"},{"vulnerable":true,"criteria":"cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*","versionStartIncluding":"9.20.9-S1","versionEndIncluding":"9.20.20-S1"}]}]}],"metrics":[{"cvssV3_1":{"version":"3.1","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"}}],"problemTypes":[{"descriptions":[{"lang":"en","type":"CWE","cweId":"CWE-606","description":"CWE-606 Unchecked Input for Loop Condition"}]}],"descriptions":[{"lang":"en","value":"If a BIND resolver is performing DNSSEC validation and encounters a maliciously crafted zone, the resolver may consume excessive CPU. Authoritative-only servers are generally unaffected, although there are circumstances where authoritative servers may make recursive queries (see: https://kb.isc.org/docs/why-does-my-authoritative-server-make-recursive-queries).\nThis issue affects BIND 9 versions 9.11.0 through 9.16.50, 9.18.0 through 9.18.46, 9.20.0 through 9.20.20, 9.21.0 through 9.21.19, 9.11.3-S1 through 9.16.50-S1, 9.18.11-S1 through 9.18.46-S1, and 9.20.9-S1 through 9.20.20-S1."}],"impacts":[{"descriptions":[{"lang":"en","value":"If this issue is encountered, the resolver may experience excessive CPU consumption and a sharp decrease in the number of queries per second that it can handle."}]}],"workarounds":[{"lang":"en","value":"This is not recommended, but disabling DNSSEC (`dnssec-validation no;`) prevents exploitation of this issue."}],"exploits":[{"lang":"en","value":"We are not aware of any active exploits."}],"solutions":[{"lang":"en","value":"Upgrade to the patched release most closely related to your current version of BIND 9: 9.18.47, 9.20.21, 9.21.20, 9.18.47-S1, or 9.20.21-S1."}],"credits":[{"lang":"en","value":"ISC would like to thank Samy Medjahed/Ap4sh for bringing this vulnerability to our attention."}],"references":[{"url":"https://kb.isc.org/docs/cve-2026-1519","name":"CVE-2026-1519","tags":["vendor-advisory"]},{"url":"https://downloads.isc.org/isc/bind9/9.18.47","tags":["patch"]},{"url":"https://downloads.isc.org/isc/bind9/9.20.21","tags":["patch"]},{"url":"https://downloads.isc.org/isc/bind9/9.21.20","tags":["patch"]}],"source":{"discovery":"EXTERNAL"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-03-25T14:55:33.427270Z","id":"CVE-2026-1519","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-03-25T14:55:40.032Z"}},{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2026/04/msg00008.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2026-04-13T09:35:57.526Z"}}]}}