{"id":"CVE-2026-81563","state":"PUBLISHED","title":"SVCB AliasMode additional-data error leaks qpcache references","description":"A BIND resolver encountering an SVCB/HTTPS AliasMode record referencing 14 or more SVCB/HTTPS ServiceMode records may fail to properly deallocate internal resources. If this happens repeatedly, resource exhaustion will eventually prevent the resolver from performing new recursive lookups.\nThis issue affects BIND 9 versions 9.18.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.18.11-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1.","publishedAt":"2026-09-16T14:00:04.129Z","updatedAt":"2026-09-17T17:47:23.137Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"isc"},"assigner":"isc","products":["ISC BIND 9"],"affected":[{"vendor":"ISC","product":"BIND 9","defaultStatus":"unaffected","versions":[{"version":"9.18.0","status":"affected","lessThanOrEqual":"9.18.50","versionType":"custom"},{"version":"9.20.0","status":"affected","lessThanOrEqual":"9.20.27","versionType":"custom"},{"version":"9.21.0","status":"affected","lessThanOrEqual":"9.21.25","versionType":"custom"},{"version":"9.18.11-S1","status":"affected","lessThanOrEqual":"9.18.50-S1","versionType":"custom"},{"version":"9.20.9-S1","status":"affected","lessThanOrEqual":"9.20.27-S1","versionType":"custom"}]}],"references":["https://kb.isc.org/docs/cve-2026-81563","https://downloads.isc.org/isc/bind9/9.20.29","https://downloads.isc.org/isc/bind9/9.21.26"],"weaknesses":["CWE-401"],"ingestedAt":"2026-10-29T20:13:15.269Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/81xxx/CVE-2026-81563.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-81563","state":"PUBLISHED","datePublished":"2026-09-16T14:00:04.129Z","dateUpdated":"2026-09-17T17:47:23.137Z","assignerShortName":"isc","assignerOrgId":"404fd4d2-a609-4245-b543-2c944a302a22","dateReserved":"2026-08-27T05:57:37.544Z"},"containers":{"cna":{"title":"SVCB AliasMode additional-data error leaks qpcache references","descriptions":[{"lang":"en","value":"A BIND resolver encountering an SVCB/HTTPS AliasMode record referencing 14 or more SVCB/HTTPS ServiceMode records may fail to properly deallocate internal resources. If this happens repeatedly, resource exhaustion will eventually prevent the resolver from performing new recursive lookups.\nThis issue affects BIND 9 versions 9.18.0 through 9.18.50, 9.20.0 through 9.20.27, 9.21.0 through 9.21.25, 9.18.11-S1 through 9.18.50-S1, and 9.20.9-S1 through 9.20.27-S1."}],"affected":[{"vendor":"ISC","product":"BIND 9","defaultStatus":"unaffected","versions":[{"version":"9.18.0","status":"affected","lessThanOrEqual":"9.18.50","versionType":"custom"},{"version":"9.20.0","status":"affected","lessThanOrEqual":"9.20.27","versionType":"custom"},{"version":"9.21.0","status":"affected","lessThanOrEqual":"9.21.25","versionType":"custom"},{"version":"9.18.11-S1","status":"affected","lessThanOrEqual":"9.18.50-S1","versionType":"custom"},{"version":"9.20.9-S1","status":"affected","lessThanOrEqual":"9.20.27-S1","versionType":"custom"}]}],"references":[{"url":"https://kb.isc.org/docs/cve-2026-81563","name":"CVE-2026-81563","tags":["vendor-advisory"]},{"url":"https://downloads.isc.org/isc/bind9/9.20.29","tags":["patch"]},{"url":"https://downloads.isc.org/isc/bind9/9.21.26","tags":["patch"]}],"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":[{"cweId":"CWE-401","lang":"en","type":"CWE","description":"CWE-401 Missing Release of Memory after Effective Lifetime"}]}],"providerMetadata":{"shortName":"isc","orgId":"404fd4d2-a609-4245-b543-2c944a302a22","dateUpdated":"2026-09-16T14:00:04.129Z"},"datePublic":"2026-09-16T00:00:00.000Z","cpeApplicability":[{"nodes":[{"operator":"OR","cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*","versionStartIncluding":"9.18.0","versionEndIncluding":"9.18.50"},{"vulnerable":true,"criteria":"cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*","versionStartIncluding":"9.20.0","versionEndIncluding":"9.20.27"},{"vulnerable":true,"criteria":"cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*","versionStartIncluding":"9.21.0","versionEndIncluding":"9.21.25"},{"vulnerable":true,"criteria":"cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*","versionStartIncluding":"9.18.11-S1","versionEndIncluding":"9.18.50-S1"},{"vulnerable":true,"criteria":"cpe:2.3:a:isc:bind:*:*:*:*:*:*:*:*","versionStartIncluding":"9.20.9-S1","versionEndIncluding":"9.20.27-S1"}]}]}],"impacts":[{"descriptions":[{"lang":"en","value":"Repeated successful attacks can result in memory use beyond configured limits until the system memory is exhausted or `named` is terminated by the operating system.  Either case results in a denial-of-service attack."}]}],"workarounds":[{"lang":"en","value":"No workarounds known."}],"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: 9.20.29, 9.21.26, or 9.20.29-S1."}],"credits":[{"lang":"en","value":"ISC would like to thank Samy Medjahed/Ap4sh for bringing this vulnerability to our attention."}],"source":{"discovery":"EXTERNAL"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2026-09-17T17:47:13.244761Z","id":"CVE-2026-81563","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","version":"2.0.3"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-09-17T17:47:23.137Z"}}]}}}