{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-81563","assignerOrgId":"404fd4d2-a609-4245-b543-2c944a302a22","state":"PUBLISHED","assignerShortName":"isc","dateReserved":"2026-08-27T05:57:37.544Z","datePublished":"2026-09-16T14:00:04.129Z","dateUpdated":"2026-09-17T17:47:23.137Z"},"containers":{"cna":{"providerMetadata":{"orgId":"404fd4d2-a609-4245-b543-2c944a302a22","shortName":"isc","dateUpdated":"2026-09-16T14:00:04.129Z"},"title":"SVCB AliasMode additional-data error leaks qpcache references","datePublic":"2026-09-16T00:00:00.000Z","affected":[{"vendor":"ISC","product":"BIND 9","versions":[{"version":"9.18.0","lessThanOrEqual":"9.18.50","status":"affected","versionType":"custom"},{"version":"9.20.0","lessThanOrEqual":"9.20.27","status":"affected","versionType":"custom"},{"version":"9.21.0","lessThanOrEqual":"9.21.25","status":"affected","versionType":"custom"},{"version":"9.18.11-S1","lessThanOrEqual":"9.18.50-S1","status":"affected","versionType":"custom"},{"version":"9.20.9-S1","lessThanOrEqual":"9.20.27-S1","status":"affected","versionType":"custom"}],"defaultStatus":"unaffected"}],"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"}]}]}],"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-401","description":"CWE-401 Missing Release of Memory after Effective Lifetime"}]}],"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."}],"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."}],"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"]}],"source":{"discovery":"EXTERNAL"},"x_generator":{"engine":"cvelib 1.8.0"}},"adp":[{"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"}}}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2026-09-17T17:47:23.137Z"}}]}}