{"id":"CVE-2020-8617","url":"https://www.cyber-defence.io/tools/cve/CVE-2020-8617","generatedAt":"2026-11-05T02:08:52.922Z","title":"Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the server.","description":"Using a specially-crafted message, an attacker may potentially cause a BIND server to reach an inconsistent state if the attacker knows (or successfully guesses) the name of a TSIG key used by the server. Since BIND, by default, configures a local session key even on servers whose configuration does not otherwise make use of it, almost all current BIND servers are vulnerable. In releases of BIND dating from March 2018 and after, an assertion check in tsig.c detects this inconsistent state and deliberately exits. Prior to the introduction of the check the server would continue operating in an inconsistent state, with potentially harmful results.","published":"2020-05-19T14:15:12.000Z","lastModified":"2026-06-17T03:26:39.000Z","status":"Modified","sourceIdentifier":"security-officer@isc.org","cvss":{"version":"3.1","score":5.9,"severity":"MEDIUM","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-617"],"affected":["isc/bind","debian/debian linux","fedoraproject/fedora","opensuse/leap","canonical/ubuntu linux"],"epss":{"score":0.93332,"percentile":0.99837,"date":"2026-11-03","history":[]},"kev":{"listed":false},"exploits":{"count":1,"verified":false,"firstPublished":"2020-05-20","source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[{"edbId":48521,"kind":"exploit","title":"BIND - 'TSIG' Denial of Service","url":"https://www.exploit-db.com/exploits/48521","sourceUrl":"https://gitlab.com/exploit-database/exploitdb/-/blob/main/exploits/multiple/dos/48521.py","file":"exploits/multiple/dos/48521.py","published":"2020-05-20","added":"2020-05-27","updated":"2020-05-27","author":"Teppei Fukuda","type":"dos","platform":"multiple","port":null,"verified":false,"codes":["CVE-2020-8617"],"tags":null,"aliases":null,"applicationUrl":null,"screenshotUrl":null,"referenceUrl":"https://github.com/knqyf263/CVE-2020-8617/blob/92a64e68cf77a5b938e0d9c04524fa6147ccb785/exploit.py"}]},"verdict":{"level":"urgent","text":"EPSS puts the probability of exploitation in the next 30 days at 93.3%, higher than 100% of all known CVEs. Patch or mitigate before the next change window."},"changes":[],"references":[{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00041.html","tags":["Mailing List","Third Party Advisory"],"source":"security-officer@isc.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00044.html","tags":["Mailing List","Third Party Advisory"],"source":"security-officer@isc.org"},{"url":"http://packetstormsecurity.com/files/157836/BIND-TSIG-Denial-Of-Service.html","tags":["Third Party Advisory","VDB Entry"],"source":"security-officer@isc.org"},{"url":"http://www.openwall.com/lists/oss-security/2020/05/19/4","tags":["Mailing List","Patch","Third Party Advisory"],"source":"security-officer@isc.org"},{"url":"https://kb.isc.org/docs/cve-2020-8617","tags":["Patch","Vendor Advisory"],"source":"security-officer@isc.org"},{"url":"https://lists.debian.org/debian-lts-announce/2020/05/msg00031.html","tags":["Mailing List","Third Party Advisory"],"source":"security-officer@isc.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JKJXVBOKZ36ER3EUCR7VRB7WGHIIMPNJ/","source":"security-officer@isc.org"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WOGCJS2XQ3SQNF4W6GLZ73LWZJ6ZZWZI/","source":"security-officer@isc.org"},{"url":"https://security.netapp.com/advisory/ntap-20200522-0002/","tags":["Third Party Advisory"],"source":"security-officer@isc.org"},{"url":"https://usn.ubuntu.com/4365-1/","tags":["Third Party Advisory"],"source":"security-officer@isc.org"},{"url":"https://usn.ubuntu.com/4365-2/","tags":["Third Party Advisory"],"source":"security-officer@isc.org"},{"url":"https://www.debian.org/security/2020/dsa-4689","tags":["Third Party Advisory"],"source":"security-officer@isc.org"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00041.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://lists.opensuse.org/opensuse-security-announce/2020-10/msg00044.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://packetstormsecurity.com/files/157836/BIND-TSIG-Denial-Of-Service.html","tags":["Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2020/05/19/4","tags":["Mailing List","Patch","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://kb.isc.org/docs/cve-2020-8617","tags":["Patch","Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2020/05/msg00031.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/JKJXVBOKZ36ER3EUCR7VRB7WGHIIMPNJ/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WOGCJS2XQ3SQNF4W6GLZ73LWZJ6ZZWZI/","source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://security.netapp.com/advisory/ntap-20200522-0002/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/4365-1/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/4365-2/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2020/dsa-4689","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2020-8617","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."}