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CVE-2026-49429

Kernel heap overflow in ZFS_IOC_USERSPACE_MANY ioctl

High7.8EPSS 0.15%
Published
Updated
Reserved
Assigned by
freebsd

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.

Scores

CVSS scores of CVE-2026-49429, by who scored it
Scored byCVSSScoreVector
CISA-ADPADP (enrichment)3.1High7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVDNVD · Analyzed3.1High7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (exploitation in 30 days)
0.15% · top 96% of all CVEs (6 Nov 2026)
CISA SSVC
Exploitation: none · Automatable: no · Technical impact: total
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.

Weakness

Affected products

  • FreeBSD · FreeBSD

    • affected 15.1-RELEASE – < p1
    • affected 15.0-RELEASE – < p11
    • affected 14.4-RELEASE – < p7
    • affected 14.3-RELEASE – < p16

References (1)

Sources

The same CVE in the primary databases and aggregators, to check against.

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Record last updated .