Security Vulnerabilities
The ZFS_IOC_SET_PROP ioctl, used by zfs-set(8), incorrectly validated the calling user such that an unprivileged user is able to set metadata on a dataset indicating that the dataset has received properties from a zfs-recv(8) stream.
Any local user can set the internal ZFS metadata flag "$hasrecvd" on datasets via ZFS_IOC_SET_PROP.
CVSS Score
3.3
EPSS Score
0.001
Published
2026-08-19
Certain system calls, such open(2) with the O_TRUNC flag set, and fspacectl(2), could incorrectly free memory in largepage objects. These operations are not permitted on largepage objects, but the implementation did not verify this.
An unprivileged local user can abuse the bug to access freed kernel memory. This can be exploited to escalate privileges.
CVSS Score
8.4
EPSS Score
0.003
Published
2026-08-19
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 Score
7.8
EPSS Score
0.002
Published
2026-08-19
The ZFS_IOC_RECV_NEW ioctl, in the heal receive path, similarly truncated a 64-bit payload size to a 32-bit integer for allocation, then used the original 64-bit size as the length for a byteswap operation.
A local user with the "receive" delegated ZFS permission can trigger kernel memory corruption via ZFS_IOC_RECV_NEW by sending a crafted receive stream in heal mode.
CVSS Score
7.8
EPSS Score
0.002
Published
2026-08-19
The kernel function that implements unlinkat(2) and funlinkat(2) validated the AT_RESOLVE_BENEATH flag but failed to pass it through to the underlying path lookup. The flag was silently dropped, so path resolution was not actually restricted.
A process that uses AT_RESOLVE_BENEATH with unlinkat(2) or funlinkat(2) to confine path resolution can in fact resolve paths above the starting directory. A caller relying on this flag for path containment may delete files outside the intended directory tree.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-08-19
The RACK setsockopt(2) handler drops the connection lock in order to copy option data from userspace, then reacquires the lock. After reacquiring, it verifies that the TCP stack had not been switched away, but did not reload its pointer to the stack's per-connection control block. If userspace switches stacks twice during this window, the check will succeed but the saved pointer will refer to freed memory.
The bug may be exploitable by an unprivileged local user to escalate privileges.
CVSS Score
8.4
EPSS Score
0.001
Published
2026-08-19
When auditing a system call executed via ptrace(PT_SC_REMOTE), the kernel passed the return value of an internal setup function to AUDIT_SYSCALL_EXIT() rather than the actual result of the executed system call. As a result, committed audit records for system calls which returned an error do not reflect the true outcome of the operation. That is, they indicate that the operation succeeded when it in fact failed.
Audit records for system calls executed via ptrace(PT_SC_REMOTE) may show an incorrect error status. An attacker with the ability to debug a process could use this to produce misleading audit trails, potentially undermining audit-based Intrusion Detection Systems (IDS).
CVSS Score
3.3
EPSS Score
0.001
Published
2026-08-19
Pages belonging to largepage shared memory objects were not explicitly wired. When sendfile(2) transmitted such an object with the SF_NOCACHE flag, it freed the underlying pages after transmission even though existing mappings still referred to them.
An unprivileged local user can abuse the bug to access freed kernel memory. This can be exploited to escalate privileges.
CVSS Score
8.8
EPSS Score
0.003
Published
2026-08-19
The RTSP handler in libalias rewrote outgoing packets into a fixed-length stack buffer without checking whether the rewritten data fit in the buffer, or whether the result fit back in the original packet.
A host sending crafted RTSP traffic from inside a NAT gateway using libalias can overflow a stack buffer, potentially achieving remote code execution in the kernel (when using ipfw(4) NAT) or in the natd(8) process (which generally runs as the root user).
CVSS Score
8.8
EPSS Score
0.003
Published
2026-08-19
When the JAIL_AT_DESC flag is specified, kern_jail_set() and kern_jail_get() released the reference to the caller's current prison before looking up the jail descriptor. If the descriptor lookup failed, error-handling paths released the same reference a second time.
An unprivileged local user can trigger a prison reference count underflow, which may cause the prison structure to be freed while still in use. When this is done on the jail host, the bug will generally result in an immediate panic. However, if the user is running in a jail, then it may be possible to exploit the bug to elevate privileges.
CVSS Score
8.8
EPSS Score
0.003
Published
2026-08-19