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.
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.
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Wed, 19 Aug 2026 13:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
cvssV3_1
|
Wed, 19 Aug 2026 12:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| First Time appeared |
Freebsd
Freebsd freebsd |
|
| Vendors & Products |
Freebsd
Freebsd freebsd |
Wed, 19 Aug 2026 05:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| 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. | |
| Title | Kernel heap overflow in ZFS_IOC_USERSPACE_MANY ioctl | |
| Weaknesses | CWE-122 | |
| References |
|
Projects
Sign in to view the affected projects.
Status: PUBLISHED
Assigner: freebsd
Published:
Updated: 2026-08-19T12:16:35.367Z
Reserved: 2026-05-29T20:24:28.616Z
Link: CVE-2026-49429
No data.
Status : Received
Published: 2026-08-19T06:17:42.513
Modified: 2026-08-19T13:17:46.030
Link: CVE-2026-49429
No data.
OpenCVE Enrichment
Updated: 2026-08-19T12:30:04Z
Weaknesses