Vulnerability details
CVE-2026-49429
FreeBSD FreeBSD
Kernel heap overflow in ZFS_IOC_USERSPACE_MANY ioctl
CVSS 3.1
7.8High
Official 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.
CVSS scores
| Score | Version | Source | Vector |
|---|---|---|---|
| 7.8High | 3.1 | CISA ADP / Vulnrichment (CISA-ADP) | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
Affected products
| Vendor | Product | Versions | Source |
|---|---|---|---|
| FreeBSD | FreeBSD | 14.3-RELEASE ≤ v < p16 | CVEProject cvelistV5 (CNA) |
| FreeBSD | FreeBSD | 14.4-RELEASE ≤ v < p7 | CVEProject cvelistV5 (CNA) |
| FreeBSD | FreeBSD | 15.0-RELEASE ≤ v < p11 | CVEProject cvelistV5 (CNA) |
| FreeBSD | FreeBSD | 15.1-RELEASE ≤ v < p1 | CVEProject cvelistV5 (CNA) |
References and advisories
1- https://security.freebsd.org/advisories/FreeBSD-SA-26:40.zfs.asc vendor-advisory
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Details
- Published
- 2026-08-19
- Last updated
- 2026-08-20
- State
- Published
- Assigner (CNA)
- freebsd
Exploit prediction (EPSS)
0.15%
Probability of exploitation in 30 days
4.4%
Percentile (among all CVEs)
SSVC assessment (CISA)
- Automatable
- No
- Exploitation
- None
- Technical impact
- Total
Weaknesses (CWE)
- CWE-122Heap-based Buffer Overflow