Krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read_CVE-2026-11850

{
    "lastseen": "",
    "description": "An integer underflow vulnerability was found in MIT krb5 in the berval2tl_data() function in plugins/kdb/ldap/libkdb_ldap/ldap_principal2.c. The function performs an unsigned subtraction (bv_len - 2) without a prior bounds check. When bv_len is 0 or 1, the subtraction wraps to a large value which is then truncated to uint16_t, yielding 0xFFFE (65534) or 0xFFFF (65535). The subsequent malloc succeeds and memcpy reads up to 65534 bytes from a 0-1 byte buffer, resulting in a heap out-of-bounds read.\nThe attack vector involves a malicious or compromised LDAP KDB backend returning a krbExtraData attribute with bv_len < 2, triggering the underflow when the KDC or kadmind reads principal data.",
    "published": "2026-06-11T09:49:07.726Z",
    "modified": "2026-06-11T09:49:07.726Z",
    "type": "cve",
    "title": "Krb5: krb5: integer underflow in berval2tl_data() leads to heap out-of-bounds read",
    "source": "redhat",
    "references": "https://access.redhat.com/security/cve/CVE-2026-11850\nhttps://bugzilla.redhat.com/show_bug.cgi?id=2459970",
    "id": "CVE-2026-11850",
    "bulletinFamily": "",
    "cwe": [
        "CWE-191"
    ],
    "cvelist": null,
    "sourceData": "",
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    "cvss": {
        "score": 5,
        "severity": "MEDIUM",
        "vector": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H",
        "version": "3.1"
    },
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        "confidentialityImpact": "",
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        "cvssV3": {
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    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "Red Hat Enterprise Linux 10",
    "version": "",
    "vendor": "Red Hat",
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    "ai_score": 0
}