Heap-based buffer overflow in FreeBSD - CVE-2026-49429
Published: July 1, 2026
Vulnerability identifier: #VU136008
CSH Severity: Low
CVSS v4.0: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Clear
CVE-ID: CVE-2026-49429
CWE-ID: CWE-122
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vendor: FreeBSD Foundation
Affected software:
FreeBSD
FreeBSD
Detailed vulnerability description
The vulnerability allows a local user to escalate privileges.
The vulnerability exists due to heap-based buffer overflow in the ZFS_IOC_USERSPACE_MANY ioctl when processing a userspace output buffer size. A local user can trigger the ioctl with a crafted 64-bit buffer size to escalate privileges.
Exploitation requires the delegated ZFS permission "userused".
How to mitigate CVE-2026-49429
Install security update from vendor's website.