Security Vulnerabilities - CVEs Published In May 2026
In the Linux kernel, the following vulnerability has been resolved:
HID: appletb-kbd: fix UAF in inactivity-timer cleanup path
Commit 38224c472a03 ("HID: appletb-kbd: fix slab use-after-free bug in
appletb_kbd_probe") added timer_delete_sync(&kbd->inactivity_timer) to
both the probe close_hw error path and appletb_kbd_remove(), but the
way it was wired in left the inactivity timer reachable during driver
tear-down via two distinct windows.
Window A -- put_device() before timer_delete_sync():
put_device(&kbd->backlight_dev->dev);
timer_delete_sync(&kbd->inactivity_timer);
The inactivity_timer softirq reads kbd->backlight_dev and calls
backlight_device_set_brightness() -> mutex_lock(&ops_lock). If a
concurrent hid_appletb_bl unbind drops the last devm reference
between these two calls, the backlight_device is freed and the
mutex_lock() touches freed memory.
Window B -- backlight cleanup before hid_hw_stop():
if (kbd->backlight_dev) {
timer_delete_sync(...);
put_device(...);
}
hid_hw_close(hdev);
hid_hw_stop(hdev);
Even after Window A is closed, hid_hw_close()/hid_hw_stop() still run
afterwards, so a late ".event" callback from the HID core (USB URB
completion on real Apple hardware) can arrive after
timer_delete_sync() drained the softirq but before put_device() drops
the reference. That callback reaches reset_inactivity_timer(), which
calls mod_timer() and re-arms the timer. The freshly re-armed timer
can then fire on the about-to-be-freed backlight_device.
Both windows produce the same KASAN slab-use-after-free:
BUG: KASAN: slab-use-after-free in __mutex_lock+0x1aab/0x21c0
Read of size 8 at addr ffff88803ee9a108 by task swapper/0/0
Call Trace:
<IRQ>
__mutex_lock
backlight_device_set_brightness
appletb_inactivity_timer
call_timer_fn
run_timer_softirq
handle_softirqs
Allocated by task N:
devm_backlight_device_register
appletb_bl_probe
Freed by task M:
(concurrent hid_appletb_bl unbind path)
Close both windows at once by reworking the tear-down in
appletb_kbd_remove() and in the probe close_hw error path so that
1) hid_hw_close()/hid_hw_stop() run before the backlight cleanup,
guaranteeing no further .event callback can fire and re-arm the
timer, and
2) inside the "if (kbd->backlight_dev)" block, timer_delete_sync()
runs before put_device(), so the softirq is drained before the
final reference is dropped.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix node_cnt race between extent node destroy and writeback
f2fs_destroy_extent_node() does not set FI_NO_EXTENT before clearing
extent nodes. When called from f2fs_drop_inode() with I_SYNC set,
concurrent kworker writeback can insert new extent nodes into the same
extent tree, racing with the destroy and triggering f2fs_bug_on() in
__destroy_extent_node(). The scenario is as follows:
drop inode writeback
- iput
- f2fs_drop_inode // I_SYNC set
- f2fs_destroy_extent_node
- __destroy_extent_node
- while (node_cnt) {
write_lock(&et->lock)
__free_extent_tree
write_unlock(&et->lock)
- __writeback_single_inode
- f2fs_outplace_write_data
- f2fs_update_read_extent_cache
- __update_extent_tree_range
// FI_NO_EXTENT not set,
// insert new extent node
} // node_cnt == 0, exit while
- f2fs_bug_on(node_cnt) // node_cnt > 0
Additionally, __update_extent_tree_range() only checks FI_NO_EXTENT for
EX_READ type, leaving EX_BLOCK_AGE updates completely unprotected.
This patch set FI_NO_EXTENT under et->lock in __destroy_extent_node(),
consistent with other callers (__update_extent_tree_range and
__drop_extent_tree) and check FI_NO_EXTENT for both EX_READ and
EX_BLOCK_AGE tree.
CVSS Score
4.7
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
smb: client: validate dacloffset before building DACL pointers
parse_sec_desc(), build_sec_desc(), and the chown path in
id_mode_to_cifs_acl() all add the server-supplied dacloffset to pntsd
before proving a DACL header fits inside the returned security
descriptor.
On 32-bit builds a malicious server can return dacloffset near
U32_MAX, wrap the derived DACL pointer below end_of_acl, and then slip
past the later pointer-based bounds checks. build_sec_desc() and
id_mode_to_cifs_acl() can then dereference DACL fields from the wrapped
pointer in the chmod/chown rewrite paths.
Validate dacloffset numerically before building any DACL pointer and
reuse the same helper at the three DACL entry points.
CVSS Score
9.8
EPSS Score
0.007
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
tracepoint: balance regfunc() on func_add() failure in tracepoint_add_func()
When a tracepoint goes through the 0 -> 1 transition, tracepoint_add_func()
invokes the subsystem's ext->regfunc() before attempting to install the
new probe via func_add(). If func_add() then fails (for example, when
allocate_probes() cannot allocate a new probe array under memory pressure
and returns -ENOMEM), the function returns the error without calling the
matching ext->unregfunc(), leaving the side effects of regfunc() behind
with no installed probe to justify them.
For syscall tracepoints this is particularly unpleasant: syscall_regfunc()
bumps sys_tracepoint_refcount and sets SYSCALL_TRACEPOINT on every task.
After a leaked failure, the refcount is stuck at a non-zero value with no
consumer, and every task continues paying the syscall trace entry/exit
overhead until reboot. Other subsystems providing regfunc()/unregfunc()
pairs exhibit similarly scoped persistent state.
Mirror the existing 1 -> 0 cleanup and call ext->unregfunc() in the
func_add() error path, gated on the same condition used there so the
unwind is symmetric with the registration.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
drm/amdkfd: validate SVM ioctl nattr against buffer size
Validate nattr field against the buffer size, preventing
out-of-bounds buffer access via user-controlled attribute count.
(cherry picked from commit 5eca8bfdfa456c3304ca77523718fe24254c172f)
CVSS Score
7.8
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: fix integer overflow on buff_pos
Fixing an integer overflow present in batadv_iv_ogm_send_to_if. The size
check is done using the int type in batadv_iv_ogm_aggr_packet whereas the
buff_pos variable uses the s16 type. This could lead to an out-of-bound
read.
CVSS Score
8.8
EPSS Score
0.003
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
drm/amdgpu/vcn4: Prevent OOB reads when parsing dec msg
Check bounds against the end of the BO whenever we access the msg.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
spi: mpc52xx: fix controller deregistration
Make sure to deregister the controller before disabling and releasing
underlying resources like interrupts and gpios during driver unbind.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
drm/xe: Fix dma-buf attachment leak in xe_gem_prime_import()
When xe_dma_buf_init_obj() fails, the attachment from
dma_buf_dynamic_attach() is not detached. Add dma_buf_detach() before
returning the error. Note: we cannot use goto out_err here because
xe_dma_buf_init_obj() already frees bo on failure, and out_err would
double-free it.
(cherry picked from commit a828eb185aac41800df8eae4b60501ccc0dbbe51)
CVSS Score
7.8
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
HID: appletb-kbd: run inactivity autodim from workqueues
The autodim code in hid-appletb-kbd takes backlight_device->ops_lock
via backlight_device_set_brightness() -> mutex_lock() from two
different atomic contexts:
* appletb_inactivity_timer() is a struct timer_list callback, so it
runs in softirq context. Every expiry triggers
BUG: sleeping function called from invalid context at kernel/locking/mutex.c:591
Call Trace:
<IRQ>
__might_resched
__mutex_lock
backlight_device_set_brightness
appletb_inactivity_timer
call_timer_fn
run_timer_softirq
* reset_inactivity_timer() is called from appletb_kbd_hid_event() and
appletb_kbd_inp_event(). On real USB hardware these run in
softirq/IRQ context (URB completion and input-event dispatch).
When the Touch Bar has already been dimmed or turned off, the
reset path calls backlight_device_set_brightness() directly to
restore brightness, producing the same warning.
Both call sites hit the same mutex_lock()-from-atomic bug. Fix them
together by moving the blocking work onto the system workqueue:
* Convert the inactivity timer from struct timer_list to
struct delayed_work; the callback (appletb_inactivity_work) now
runs in process context where mutex_lock() is legal.
* Add a dedicated struct work_struct restore_brightness_work and have
reset_inactivity_timer() schedule it instead of calling
backlight_device_set_brightness() directly.
Cancel both works synchronously during driver tear-down alongside the
existing backlight reference drop.
The semantics are unchanged (same delays, same state transitions on
dim, turn-off and user activity); only the execution context of the
sleeping call changes. The timer field and callback are renamed to
match their new type; reset_inactivity_timer() keeps its name because
it is invoked from input event paths that read naturally as "reset
the inactivity timer".
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-28