{"id":"CVE-2026-49429","aliases":[],"url":"https://o3.security/vulnerability/CVE-2026-49429","summary":"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…","details":"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.\n\nA local user with the \"userused\" delegated ZFS permission can trigger a kernel heap overflow via the ZFS_IOC_USERSPACE_MANY ioctl, potentially escalating privileges.","published":"2026-08-19T05:15:21.198Z","modified":"2026-08-19T05:15:21.198Z","cvss":null,"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[],"fix":null,"references":[{"type":"ADVISORY","url":"https://security.freebsd.org/advisories/FreeBSD-SA-26:40.zfs.asc"}],"provenance":{"sources":["OSV.dev","NVD","FIRST.org (EPSS)"],"lastVerified":"2026-08-19T05:15:21.198Z"}}