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.
Metrics
Affected Vendors & Products
References
History
Tue, 01 Sep 2026 22:00:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| CPEs | cpe:2.3:o:freebsd:freebsd:14.3:-:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p10:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p11:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p12:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p13:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p14:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p15:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p1:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p2:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p3:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p4:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p5:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p6:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p7:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p8:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.3:p9:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.4:-:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.4:p1:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.4:p2:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.4:p3:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.4:p4:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.4:p5:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.4:p6:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:14.4:rc1:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.0:-:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.0:p10:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.0:p1:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.0:p2:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.0:p3:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.0:p4:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.0:p5:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.0:p6:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.0:p7:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.0:p8:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.0:p9:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.1:-:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.1:rc2:*:*:*:*:*:* cpe:2.3:o:freebsd:freebsd:15.1:rc3-p1:*:*:*:*:*:* |
Thu, 20 Aug 2026 05:30:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Metrics |
ssvc
|
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 |
|
Status: PUBLISHED
Assigner: freebsd
Published: 2026-08-19T05:15:21.198Z
Updated: 2026-08-20T03:55:49.215Z
Reserved: 2026-05-29T20:24:28.616Z
Link: CVE-2026-49429
Updated: 2026-08-19T12:16:32.478Z
Status : Analyzed
Published: 2026-08-19T06:17:42.513
Modified: 2026-09-01T20:05:50.613
Link: CVE-2026-49429
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