CVE-2026-40686_CVE-2026-40686

3.7 / 10

LOW

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N

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.

Basic Information

ID CVE-2026-40686

Source mitre

Published Apr 30, 2026 at 00:00

Modified Apr 30, 2026 at 21:29

Affected Product

Vendor Exim

Product Exim

Affected Versions Exim Exim 0

CWE Classification

CWE-125

References

{
    "lastseen": "",
    "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.",
    "published": "2026-04-30T00:00:00.000Z",
    "modified": "2026-04-30T21:29:23.505Z",
    "type": "cve",
    "title": "CVE-2026-40686",
    "source": "mitre",
    "references": "https://exim.org/static/doc/security/CVE-2025-40686.txt\nhttps://www.openwall.com/lists/oss-security/2026/04/30/21\nhttps://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40686.assessment\nhttps://code.exim.org/exim/exim/commit/f2570bde16fb4d4a1242ff363a4c4eecf6372efc",
    "id": "CVE-2026-40686",
    "bulletinFamily": "",
    "cwe": [
        "CWE-125"
    ],
    "cvelist": null,
    "sourceData": "Exim Exim 0",
    "sourceHref": "",
    "cvss": {
        "score": 3.7,
        "severity": "LOW",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N",
        "version": "3.1"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Exim",
    "version": "0",
    "vendor": "Exim",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}