{"cve":"CVE-2026-40684","nvd":{"published":"2026-04-30T22:16:25.477","modified":"2026-06-17T10:45:34.197","status":"Modified","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.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","score":7.5},"cwes":["CWE-684"],"references":["https://code.exim.org/exim/exim/commit/628bbaca7672748d941a12e7cd5f0122a4e18c81","https://exim.org/static/doc/security/CVE-2026-40684.txt","https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40684.assessment","https://www.openwall.com/lists/oss-security/2026/04/30/21","http://www.openwall.com/lists/oss-security/2026/05/01/11"],"products":["exim:exim"],"source":"nvd","synced_at":"2026-10-19T22:33:09.003606135+00:00"},"epss":{"cve":"CVE-2026-40684","score":0.00362,"percentile":0.30052,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}