{"id":"CVE-2023-2911","state":"PUBLISHED","title":"Exceeding the recursive-clients quota may cause named to terminate unexpectedly when stale-answer-client-timeout is set to 0","description":"If the `recursive-clients` quota is reached on a BIND 9 resolver configured with both `stale-answer-enable yes;` and `stale-answer-client-timeout 0;`, a sequence of serve-stale-related lookups could cause `named` to loop and terminate unexpectedly due to a stack overflow.\nThis issue affects BIND 9 versions 9.16.33 through 9.16.41, 9.18.7 through 9.18.15, 9.16.33-S1 through 9.16.41-S1, and 9.18.11-S1 through 9.18.15-S1.","publishedAt":"2023-06-21T16:26:36.587Z","updatedAt":"2025-02-13T16:49:00.351Z","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":"9.16.33","status":"affected","lessThanOrEqual":"9.16.41","versionType":"custom"},{"version":"9.18.7","status":"affected","lessThanOrEqual":"9.18.15","versionType":"custom"},{"version":"9.16.33-S1","status":"affected","lessThanOrEqual":"9.16.41-S1","versionType":"custom"},{"version":"9.18.11-S1","status":"affected","lessThanOrEqual":"9.18.15-S1","versionType":"custom"}]}],"references":["https://kb.isc.org/docs/cve-2023-2911","http://www.openwall.com/lists/oss-security/2023/06/21/6","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U3K6AJK7RRSR53HRF5GGKPA6PDUDWOD2/","https://www.debian.org/security/2023/dsa-5439","https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SEFCEVCTYEMKTWA7V7EYPI5YQQ4JWDLI/","https://security.netapp.com/advisory/ntap-20230703-0010/"],"weaknesses":[],"ingestedAt":"2026-10-29T20:05:52.290Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2023/2xxx/CVE-2023-2911.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.1","cveMetadata":{"cveId":"CVE-2023-2911","state":"PUBLISHED","datePublished":"2023-06-21T16:26:36.587Z","dateUpdated":"2025-02-13T16:49:00.351Z","assignerShortName":"isc","assignerOrgId":"404fd4d2-a609-4245-b543-2c944a302a22","dateReserved":"2023-05-26T11:20:45.872Z"},"containers":{"cna":{"title":"Exceeding the recursive-clients quota may cause named to terminate unexpectedly when stale-answer-client-timeout is set to 0","descriptions":[{"lang":"en","value":"If the `recursive-clients` quota is reached on a BIND 9 resolver configured with both `stale-answer-enable yes;` and `stale-answer-client-timeout 0;`, a sequence of serve-stale-related lookups could cause `named` to loop and terminate unexpectedly due to a stack overflow.\nThis issue affects BIND 9 versions 9.16.33 through 9.16.41, 9.18.7 through 9.18.15, 9.16.33-S1 through 9.16.41-S1, and 9.18.11-S1 through 9.18.15-S1."}],"affected":[{"vendor":"ISC","product":"BIND 9","defaultStatus":"unaffected","versions":[{"version":"9.16.33","status":"affected","lessThanOrEqual":"9.16.41","versionType":"custom"},{"version":"9.18.7","status":"affected","lessThanOrEqual":"9.18.15","versionType":"custom"},{"version":"9.16.33-S1","status":"affected","lessThanOrEqual":"9.16.41-S1","versionType":"custom"},{"version":"9.18.11-S1","status":"affected","lessThanOrEqual":"9.18.15-S1","versionType":"custom"}]}],"references":[{"url":"https://kb.isc.org/docs/cve-2023-2911","name":"CVE-2023-2911","tags":["vendor-advisory"]},{"url":"http://www.openwall.com/lists/oss-security/2023/06/21/6"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U3K6AJK7RRSR53HRF5GGKPA6PDUDWOD2/"},{"url":"https://www.debian.org/security/2023/dsa-5439"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SEFCEVCTYEMKTWA7V7EYPI5YQQ4JWDLI/"},{"url":"https://security.netapp.com/advisory/ntap-20230703-0010/"}],"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"}}],"providerMetadata":{"shortName":"isc","orgId":"404fd4d2-a609-4245-b543-2c944a302a22","dateUpdated":"2023-07-03T15:06:21.382Z"},"datePublic":"2023-06-21T00:00:00.000Z","impacts":[{"descriptions":[{"lang":"en","value":"By sending specific queries to the resolver, an attacker can cause `named` to terminate unexpectedly."}]}],"workarounds":[{"lang":"en","value":"Setting `stale-answer-client-timeout` to `off` or to a non-zero value prevents the issue.\n\nUsers of versions 9.18.10, 9.16.36, 9.16.36-S1 or older who are unable to upgrade should set `stale-answer-client-timeout` to `off`; using a non-zero value with these older versions leaves `named` vulnerable to CVE-2022-3924.\n\nAlthough it is possible to set the `recursive-clients` limit to a high number to reduce the likelihood of this scenario, this is not recommended; the limit on `recursive-clients` is important for preventing exhaustion of server resources. The limit cannot be disabled entirely."}],"exploits":[{"lang":"en","value":"This flaw was discovered in internal testing. 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: 9.16.42, 9.18.16, 9.16.42-S1, or 9.18.16-S1."}],"source":{"discovery":"INTERNAL"}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://kb.isc.org/docs/cve-2023-2911","name":"CVE-2023-2911","tags":["vendor-advisory","x_transferred"]},{"url":"http://www.openwall.com/lists/oss-security/2023/06/21/6","tags":["x_transferred"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/U3K6AJK7RRSR53HRF5GGKPA6PDUDWOD2/","tags":["x_transferred"]},{"url":"https://www.debian.org/security/2023/dsa-5439","tags":["x_transferred"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/SEFCEVCTYEMKTWA7V7EYPI5YQQ4JWDLI/","tags":["x_transferred"]},{"url":"https://security.netapp.com/advisory/ntap-20230703-0010/","tags":["x_transferred"]}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2024-08-02T06:41:03.760Z"}},{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"timestamp":"2024-12-06T18:32:18.833805Z","id":"CVE-2023-2911","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":"2024-12-06T18:32:26.092Z"}}]}}}