CVE-2026-11850
Full vulnerability record from the local CVENow database.
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. The 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.
Severity
MEDIUM
CVSS score
5.0
(v3.1)
Vulnerability status
Awaiting Analysis
Source identifier
Published
2026-06-11 10:16:21.217000
Last modified
2026-10-31 16:17:01.297000
View original CVE JSON
{
"id": "CVE-2026-11850",
"sourceIdentifier": "[email protected]",
"published": "2026-06-11T10:16:21.217",
"lastModified": "2026-10-31T16:17:01.297",
"vulnStatus": "Awaiting Analysis",
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "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."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "Red Hat",
"product": "Red Hat Hardened Images",
"defaultStatus": "affected",
"collectionURL": "https://catalog.redhat.com/software/containers/",
"packageName": "krb5-main",
"cpes": [
"cpe:/a:redhat:hummingbird:1"
],
"versions": [
{
"version": "1.22.2-8.hum1",
"lessThan": "*",
"versionType": "rpm",
"status": "unaffected"
}
]
},
{
"vendor": "Red Hat",
"product": "Red Hat Enterprise Linux 10",
"defaultStatus": "affected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "krb5",
"cpes": [
"cpe:/o:redhat:enterprise_linux:10"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat Enterprise Linux 6",
"defaultStatus": "affected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "krb5",
"cpes": [
"cpe:/o:redhat:enterprise_linux:6"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat Enterprise Linux 7",
"defaultStatus": "affected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "krb5",
"cpes": [
"cpe:/o:redhat:enterprise_linux:7"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat Enterprise Linux 8",
"defaultStatus": "affected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "krb5",
"cpes": [
"cpe:/o:redhat:enterprise_linux:8"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat Enterprise Linux 9",
"defaultStatus": "affected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "krb5",
"cpes": [
"cpe:/o:redhat:enterprise_linux:9"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat OpenShift Container Platform 4",
"defaultStatus": "affected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "openshift/ose-rhel-coreos-8",
"cpes": [
"cpe:/a:redhat:openshift:4"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat OpenShift Container Platform 4",
"defaultStatus": "affected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "openshift/ose-rhel-coreos-9",
"cpes": [
"cpe:/a:redhat:openshift:4"
]
},
{
"vendor": "Red Hat",
"product": "Red Hat OpenShift Container Platform 5",
"defaultStatus": "affected",
"collectionURL": "https://access.redhat.com/downloads/content/package-browser/",
"packageName": "openshift/ose-rhel-coreos-9",
"cpes": [
"cpe:/a:redhat:openshift:5"
]
}
]
}
],
"metrics": {
"cvssMetricV31": [
{
"source": "[email protected]",
"type": "Secondary",
"cvssData": {
"version": "3.1",
"vectorString": "CVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:L/I:N/A:H",
"baseScore": 5.0,
"baseSeverity": "MEDIUM",
"attackVector": "NETWORK",
"attackComplexity": "HIGH",
"privilegesRequired": "HIGH",
"userInteraction": "NONE",
"scope": "UNCHANGED",
"confidentialityImpact": "LOW",
"integrityImpact": "NONE",
"availabilityImpact": "HIGH"
},
"exploitabilityScore": 0.7,
"impactScore": 4.2
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"timestamp": "2026-06-11T12:35:21.860008Z",
"id": "CVE-2026-11850",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "partial"
}
],
"role": "CISA Coordinator",
"version": "2.0.3"
}
}
]
},
"weaknesses": [
{
"source": "[email protected]",
"type": "Secondary",
"description": [
{
"lang": "en",
"value": "CWE-191"
}
]
}
],
"references": [
{
"url": "https://access.redhat.com/errata/RHSA-2026:25520",
"source": "[email protected]"
},
{
"url": "https://access.redhat.com/security/cve/CVE-2026-11850",
"source": "[email protected]"
},
{
"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2459970",
"source": "[email protected]"
}
]
}