CVE-2026-49429CWE-122

CVE-2026-49429

High · published August 19, 2026

CVSS v3.1
7.8
EPSS
0%
Percentile
4.1
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
7.8 · HIGH
Vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
Not supplied
EPSS
0.00153 · 4.1th percentile
Weakness
CWE-122 · Heap-based Buffer Overflow
Published
2026-08-19T10:17Z
Affected products (38)
ProductVersionsFixed in
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
freebsd/freebsdall versions—
References (1)
https://security.freebsd.org/advisories/FreeBSD-SA-26:40.zfs.asc · [email protected]
EPSS history
Timeline
  • 19 AUG 05:15Z
    Kernel heap overflow in ZFS_IOC_USERSPACE_MANY ioctl
    cvelistv5