{"cve":"CVE-2026-40686","nvd":{"published":"2026-04-30T22:16:25.787","modified":"2026-06-17T10:45:34.447","status":"Analyzed","description":"In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","score":5.3},"cwes":["CWE-125"],"references":["https://code.exim.org/exim/exim/commit/f2570bde16fb4d4a1242ff363a4c4eecf6372efc","https://exim.org/static/doc/security/CVE-2026-40686.txt","https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40686.assessment","https://www.openwall.com/lists/oss-security/2026/04/30/21"],"products":["exim:exim"],"source":"nvd","synced_at":"2026-10-19T22:33:09.003606135+00:00"},"epss":{"cve":"CVE-2026-40686","score":0.00246,"percentile":0.15937,"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."]}