{"dataType": "CVE_RECORD", "cveMetadata": {"state": "PUBLISHED", "cveId": "CVE-2026-40684", "assignerOrgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "assignerShortName": "mitre", "dateUpdated": "2026-05-01T01:16:53.294Z", "dateReserved": "2026-04-14T00:00:00.000Z", "datePublished": "2026-04-30T00:00:00.000Z"}, "containers": {"cna": {"affected": [{"defaultStatus": "unaffected", "product": "Exim", "vendor": "Exim", "versions": [{"lessThan": "4.99.2", "status": "affected", "version": "0", "versionType": "semver"}]}], "descriptions": [{"lang": "en", "value": "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."}], "metrics": [{"cvssV3_1": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 5.9, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "format": "CVSS", "scenarios": [{"lang": "en", "value": "GENERAL"}]}], "problemTypes": [{"descriptions": [{"cweId": "CWE-684", "description": "CWE-684 Incorrect Provision of Specified Functionality", "lang": "en", "type": "CWE"}]}], "providerMetadata": {"orgId": "8254265b-2729-46b6-b9e3-3dfca2d5bfca", "shortName": "mitre", "dateUpdated": "2026-05-01T01:16:53.294Z"}, "references": [{"url": "https://www.openwall.com/lists/oss-security/2026/04/30/21"}, {"url": "https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40684.assessment"}, {"url": "https://code.exim.org/exim/exim/commit/628bbaca7672748d941a12e7cd5f0122a4e18c81"}, {"url": "https://exim.org/static/doc/security/CVE-2026-40684.txt"}], "x_generator": {"engine": "enrichogram 0.0.1"}, "cpeApplicability": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:exim:exim:*:*:*:*:*:*:*:*", "versionEndExcluding": "4.99.2"}]}]}]}}, "dataVersion": "5.2"}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "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."}], "id": "CVE-2026-40684", "lastModified": "2026-05-01T02:16:02.843", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 5.9, "baseSeverity": "MEDIUM", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 3.6, "source": "cve@mitre.org", "type": "Secondary"}]}, "published": "2026-04-30T22:16:25.477", "references": [{"source": "cve@mitre.org", "url": "https://code.exim.org/exim/exim/commit/628bbaca7672748d941a12e7cd5f0122a4e18c81"}, {"source": "cve@mitre.org", "url": "https://exim.org/static/doc/security/CVE-2026-40684.txt"}, {"source": "cve@mitre.org", "url": "https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40684.assessment"}, {"source": "cve@mitre.org", "url": "https://www.openwall.com/lists/oss-security/2026/04/30/21"}], "sourceIdentifier": "cve@mitre.org", "vulnStatus": "Received", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-684"}], "source": "cve@mitre.org", "type": "Secondary"}]}

{}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "semver", "value": "[0,4.99.2)"}}], "enrichment": {"confidence": 95.0, "confidence_source": "inferred", "scores": [{"score": 95.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Exim", "source": "cna", "vendor": "Exim"}, "product": "exim", "vendor": "exim"}], "created": "2026-04-30T23:00:04.342996+00:00", "title": "Denial of Service via malformed DNS PTR records exploits dn_expand bug in Exim on musl systems", "updated": "2026-05-01T05:30:09.820260+00:00", "vendors": ["exim", "exim$PRODUCT$exim"]}