{"id":"CVE-2026-40684","url":"https://www.cyber-defence.io/tools/cve/CVE-2026-40684","generatedAt":"2026-10-28T03:41:12.535Z","title":"In Exim before 4.99.2, on systems using musl libc (not glibc), an attacker can crash the connection instance when malformed DNS data is present in PTR records.","description":"In Exim before 4.99.2, on systems using musl libc (not glibc), an attacker can crash the connection instance when malformed DNS data is present in PTR records. This is caused by a dn_expand oddity in octal printing.","published":"2026-04-30T22:16:25.000Z","lastModified":"2026-06-17T10:45:34.000Z","status":"Modified","sourceIdentifier":"cve@mitre.org","cvss":{"version":"3.1","score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"},"cwe":["CWE-684"],"affected":["exim/exim"],"epss":{"score":0.00362,"percentile":0.29853,"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":"high","text":"High impact if exploited, but EPSS currently rates exploitation as unlikely (0.36%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit."},"changes":[],"references":[{"url":"https://code.exim.org/exim/exim/commit/628bbaca7672748d941a12e7cd5f0122a4e18c81","tags":["Patch"],"source":"cve@mitre.org"},{"url":"https://exim.org/static/doc/security/CVE-2026-40684.txt","tags":["Broken Link"],"source":"cve@mitre.org"},{"url":"https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40684.assessment","tags":["Vendor Advisory"],"source":"cve@mitre.org"},{"url":"https://www.openwall.com/lists/oss-security/2026/04/30/21","tags":["Mailing List","Third Party Advisory"],"source":"cve@mitre.org"},{"url":"http://www.openwall.com/lists/oss-security/2026/05/01/11","source":"af854a3a-2127-422b-91ae-364da2661108"}],"sources":{"nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-40684","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."}