{"id":"CVE-2018-5738","url":"https://www.cyber-defence.io/tools/cve/CVE-2018-5738","generatedAt":"2026-10-28T21:21:41.944Z","title":"The intended (and documented) behavior is that if an operator has not specified a value for the \"allow-recursion\" setting, it SHOULD default to one of the following: none, if \"recursion no;\" is set in named.conf; a value inherited from the…","description":"Change #4777 (introduced in October 2017) introduced an unforeseen issue in releases which were issued after that date, affecting which clients are permitted to make recursive queries to a BIND nameserver. The intended (and documented) behavior is that if an operator has not specified a value for the \"allow-recursion\" setting, it SHOULD default to one of the following: none, if \"recursion no;\" is set in named.conf; a value inherited from the \"allow-query-cache\" or \"allow-query\" settings IF \"recursion yes;\" (the default for that setting) AND match lists are explicitly set for \"allow-query-cache\" or \"allow-query\" (see the BIND9 Administrative Reference Manual section 6.2 for more details); or the intended default of \"allow-recursion {localhost; localnets;};\" if \"recursion yes;\" is in effect and no values are explicitly set for \"allow-query-cache\" or \"allow-query\". However, because of the regression introduced by change #4777, it is possible when \"recursion yes;\" is in effect and no match list values are provided for \"allow-query-cache\" or \"allow-query\" for the setting of \"allow-recursion\" to inherit a setting of all hosts from the \"allow-query\" setting default, improperly permitting recursion to all clients. Affects BIND 9.9.12, 9.10.7, 9.11.3, 9.12.0->9.12.1-P2, the development release 9.13.0, and also releases 9.9.12-S1, 9.10.7-S1, 9.11.3-S1, and 9.11.3-S2 from BIND 9 Supported Preview Edition.","published":"2019-01-16T20:29:01.000Z","lastModified":"2026-06-17T02:00:41.000Z","status":"Modified","sourceIdentifier":"security-officer@isc.org","cvss":{"version":"3.0","score":7.5,"severity":"HIGH","vector":"CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"},"cwe":["CWE-200"],"affected":["isc/bind","canonical/ubuntu linux"],"epss":{"score":0.1116,"percentile":0.95925,"date":"2026-10-27","history":[]},"kev":{"listed":false},"exploits":{"count":0,"verified":false,"firstPublished":null,"source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 11.2%, higher than 96% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"http://www.securitytracker.com/id/1041115","tags":["Third Party Advisory","VDB Entry"],"source":"security-officer@isc.org"},{"url":"https://kb.isc.org/docs/aa-01616","tags":["Mitigation","Vendor Advisory"],"source":"security-officer@isc.org"},{"url":"https://security.gentoo.org/glsa/201903-13","tags":["Third Party Advisory"],"source":"security-officer@isc.org"},{"url":"https://security.netapp.com/advisory/ntap-20190830-0002/","source":"security-officer@isc.org"},{"url":"https://usn.ubuntu.com/3683-1/","tags":["Third Party Advisory"],"source":"security-officer@isc.org"},{"url":"http://www.securitytracker.com/id/1041115","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://kb.isc.org/docs/aa-01616","tags":["Mitigation","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.gentoo.org/glsa/201903-13","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20190830-0002/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/3683-1/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2018-5738","epss":"https://www.first.org/epss/","kev":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog","exploitdb":"https://www.exploit-db.com/"},"licence":"CC BY 4.0 — link back to the CVE Explorer if you publish the results; upstream data remains subject to its own terms."}