CVE-2026-49429
Full vulnerability record from the local CVENow database.
Description
The ZFS_IOC_USERSPACE_MANY ioctl, used by zfs-userspace(8), truncated a 64-bit output buffer size to a 32-bit integer for the kernel allocation, but used the original 64-bit size as the buffer limit when writing records. A local user with the "userused" delegated ZFS permission can trigger a kernel heap overflow via the ZFS_IOC_USERSPACE_MANY ioctl, potentially escalating privileges.
Severity
HIGH
CVSS score
7.8
(v3.1)
Vulnerability status
Analyzed
Source identifier
Published
2026-08-19 06:17:42.513000
Last modified
2026-11-09 20:10:00.200000
View original CVE JSON
{
"id": "CVE-2026-49429",
"sourceIdentifier": "[email protected]",
"published": "2026-08-19T06:17:42.513",
"lastModified": "2026-11-09T20:10:00.200",
"vulnStatus": "Analyzed",
"cveTags": [],
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"lang": "en",
"value": "The ZFS_IOC_USERSPACE_MANY ioctl, used by zfs-userspace(8), truncated a 64-bit output buffer size to a 32-bit integer for the kernel allocation, but used the original 64-bit size as the buffer limit when writing records.\n\nA local user with the \"userused\" delegated ZFS permission can trigger a kernel heap overflow via the ZFS_IOC_USERSPACE_MANY ioctl, potentially escalating privileges."
},
{
"lang": "es",
"value": "El ioctl ZFS_IOC_USERSPACE_MANY, utilizado por zfs-userspace(8), truncó un tamaño de búfer de salida de 64 bits a un entero de 32 bits para la asignación del kernel, pero usó el tamaño original de 64 bits como límite del búfer al escribir registros.\n\nUn usuario local con el permiso ZFS delegado ’userused’ puede desencadenar un desbordamiento de montículo del kernel a través del ioctl ZFS_IOC_USERSPACE_MANY, escalando privilegios potencialmente."
}
],
"affected": [
{
"source": "[email protected]",
"affectedData": [
{
"vendor": "FreeBSD",
"product": "FreeBSD",
"defaultStatus": "unknown",
"modules": [
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"privilegesRequired": "LOW",
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"references": [
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"url": "https://security.freebsd.org/advisories/FreeBSD-SA-26:40.zfs.asc",
"source": "[email protected]",
"tags": [
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}
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}