{"id":"CVE-2018-6789","url":"https://www.cyber-defence.io/tools/cve/CVE-2018-6789","generatedAt":"2026-10-28T21:18:08.638Z","title":"Exim Buffer Overflow Vulnerability","description":"An issue was discovered in the base64d function in the SMTP listener in Exim before 4.90.1. By sending a handcrafted message, a buffer overflow may happen. This can be used to execute code remotely.","published":"2018-02-08T23:29:01.000Z","lastModified":"2026-06-17T02:02:17.000Z","status":"Analyzed","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":9.8,"severity":"CRITICAL","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"},"cwe":["CWE-120"],"affected":["exim/exim","debian/debian linux","canonical/ubuntu linux"],"epss":{"score":0.82137,"percentile":0.99653,"date":"2026-10-27","history":[]},"kev":{"listed":true,"dateAdded":"2021-11-03","dueDate":"2022-05-03","knownRansomwareCampaignUse":"Known","notes":"Apply updates per vendor instructions.\nhttps://nvd.nist.gov/vuln/detail/CVE-2018-6789"},"exploits":{"count":2,"verified":false,"firstPublished":"2018-05-02","source":"Exploit-DB (https://gitlab.com/exploit-database/exploitdb)","entries":[{"edbId":45671,"kind":"exploit","title":"exim 4.90 - Remote Code Execution","url":"https://www.exploit-db.com/exploits/45671","sourceUrl":"https://gitlab.com/exploit-database/exploitdb/-/blob/main/exploits/linux/remote/45671.py","file":"exploits/linux/remote/45671.py","published":"2018-10-24","added":"2018-10-24","updated":"2018-10-25","author":"hackk.gr","type":"remote","platform":"linux","port":25,"verified":false,"codes":["CVE-2018-6789"],"tags":"Remote","aliases":null,"applicationUrl":null,"screenshotUrl":null,"referenceUrl":null},{"edbId":44571,"kind":"exploit","title":"Exim < 4.90.1 - 'base64d' Remote Code Execution","url":"https://www.exploit-db.com/exploits/44571","sourceUrl":"https://gitlab.com/exploit-database/exploitdb/-/blob/main/exploits/linux/remote/44571.py","file":"exploits/linux/remote/44571.py","published":"2018-05-02","added":"2018-05-02","updated":"2018-05-02","author":"straight_blast","type":"remote","platform":"linux","port":25,"verified":false,"codes":["CVE-2018-6789"],"tags":"Remote","aliases":null,"applicationUrl":null,"screenshotUrl":null,"referenceUrl":"https://medium.com/@straightblast426/my-poc-walk-through-for-cve-2018-6789-2e402e4ff588"}]},"verdict":{"level":"urgent","text":"Known to be exploited in the wild (CISA KEV, CISA remediation deadline 3 May 2022). Treat as an emergency change: patch or isolate now, then hunt for prior compromise."},"changes":[],"references":[{"url":"http://openwall.com/lists/oss-security/2018/02/10/2","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2018/02/07/2","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.securityfocus.com/bid/103049","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"http://www.securitytracker.com/id/1040461","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"https://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en/","tags":["Exploit","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://exim.org/static/doc/security/CVE-2018-6789.txt","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c6855f1abecf1","tags":["Patch"],"source":"cve@mitre.org"},{"url":"https://lists.debian.org/debian-lts-announce/2018/02/msg00009.html","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://usn.ubuntu.com/3565-1/","tags":["Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://www.debian.org/security/2018/dsa-4110","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"https://www.exploit-db.com/exploits/44571/","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"https://www.exploit-db.com/exploits/45671/","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"cve@mitre.org"},{"url":"http://openwall.com/lists/oss-security/2018/02/10/2","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://packetstormsecurity.com/files/162959/Exim-base64d-Buffer-Overflow.html","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.openwall.com/lists/oss-security/2018/02/07/2","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securityfocus.com/bid/103049","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"http://www.securitytracker.com/id/1040461","tags":["Broken Link","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://devco.re/blog/2018/03/06/exim-off-by-one-RCE-exploiting-CVE-2018-6789-en/","tags":["Exploit","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://exim.org/static/doc/security/CVE-2018-6789.txt","tags":["Vendor Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.exim.org/exim.git/commit/cf3cd306062a08969c41a1cdd32c6855f1abecf1","tags":["Patch"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://lists.debian.org/debian-lts-announce/2018/02/msg00009.html","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://usn.ubuntu.com/3565-1/","tags":["Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.debian.org/security/2018/dsa-4110","tags":["Mailing List","Third Party Advisory"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.exploit-db.com/exploits/44571/","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.exploit-db.com/exploits/45671/","tags":["Exploit","Third Party Advisory","VDB Entry"],"source":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2018-6789","tags":["US Government Resource"],"source":"134c704f-9b21-4f2e-91b3-4a467353bcc0"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2018-6789","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."}