Linux: >> Linux Kernel >> 5.18.5 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/sysfs: fix use-after-free in state_show()
state_show() reads kdamond->damon_ctx without holding damon_sysfs_lock.
This allows a use-after-free race:
CPU 0 CPU 1
----- -----
state_show() damon_sysfs_turn_damon_on()
ctx = kdamond->damon_ctx; mutex_lock(&damon_sysfs_lock);
damon_destroy_ctx(kdamond->damon_ctx);
kdamond->damon_ctx = NULL;
mutex_unlock(&damon_sysfs_lock);
damon_is_running(ctx); /* ctx is freed */
mutex_lock(&ctx->kdamond_lock); /* UAF */
(The race can also occur with damon_sysfs_kdamonds_rm_dirs() and
damon_sysfs_kdamond_release(), which free or replace the context under
damon_sysfs_lock.)
Fix by taking damon_sysfs_lock before dereferencing the context, mirroring
the locking used in pid_show().
The bug has existed since state_show() first accessed kdamond->damon_ctx.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-23
In the Linux kernel, the following vulnerability has been resolved:
libceph: fix invalid accesses to ceph_connection_v1_info
There is a place where generic code in messenger.c is reading and
another place where it is writing to con->v1 union member without
checking that the union member is active (i.e. msgr1 is in use).
On 64-bit systems, con->v1.auth_retry overlaps with con->v2.out_iter,
so such a read is almost guaranteed to return a bogus value instead of
0 when msgr2 is in use. This ends up being fairly benign because the
side effect is just the invalidation of the authorizer and successive
fetching of new tickets.
con->v1.connect_seq overlaps with con->v2.conn_bufs and the fact that
it's being written to can cause more serious consequences, but luckily
it's not something that happens often.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-23
In the Linux kernel, the following vulnerability has been resolved:
dmaengine: ti: edma: Fix memory allocation size for queue_priority_map
Fix a critical memory allocation bug in edma_setup_from_hw() where
queue_priority_map was allocated with insufficient memory. The code
declared queue_priority_map as s8 (*)[2] (pointer to array of 2 s8),
but allocated memory using sizeof(s8) instead of the correct size.
This caused out-of-bounds memory writes when accessing:
queue_priority_map[i][0] = i;
queue_priority_map[i][1] = i;
The bug manifested as kernel crashes with "Oops - undefined instruction"
on ARM platforms (BeagleBoard-X15) during EDMA driver probe, as the
memory corruption triggered kernel hardening features on Clang.
Change the allocation to use sizeof(*queue_priority_map) which
automatically gets the correct size for the 2D array structure.
CVSS Score
7.1
EPSS Score
0.0
Published
2025-09-23
In the Linux kernel, the following vulnerability has been resolved:
can: xilinx_can: xcan_write_frame(): fix use-after-free of transmitted SKB
can_put_echo_skb() takes ownership of the SKB and it may be freed
during or after the call.
However, xilinx_can xcan_write_frame() keeps using SKB after the call.
Fix that by only calling can_put_echo_skb() after the code is done
touching the SKB.
The tx_lock is held for the entire xcan_write_frame() execution and
also on the can_get_echo_skb() side so the order of operations does not
matter.
An earlier fix commit 3d3c817c3a40 ("can: xilinx_can: Fix usage of skb
memory") did not move the can_put_echo_skb() call far enough.
[mkl: add "commit" in front of sha1 in patch description]
[mkl: fix indention]
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-23
In the Linux kernel, the following vulnerability has been resolved:
wifi: brcmfmac: fix use-after-free when rescheduling brcmf_btcoex_info work
The brcmf_btcoex_detach() only shuts down the btcoex timer, if the
flag timer_on is false. However, the brcmf_btcoex_timerfunc(), which
runs as timer handler, sets timer_on to false. This creates critical
race conditions:
1.If brcmf_btcoex_detach() is called while brcmf_btcoex_timerfunc()
is executing, it may observe timer_on as false and skip the call to
timer_shutdown_sync().
2.The brcmf_btcoex_timerfunc() may then reschedule the brcmf_btcoex_info
worker after the cancel_work_sync() has been executed, resulting in
use-after-free bugs.
The use-after-free bugs occur in two distinct scenarios, depending on
the timing of when the brcmf_btcoex_info struct is freed relative to
the execution of its worker thread.
Scenario 1: Freed before the worker is scheduled
The brcmf_btcoex_info is deallocated before the worker is scheduled.
A race condition can occur when schedule_work(&bt_local->work) is
called after the target memory has been freed. The sequence of events
is detailed below:
CPU0 | CPU1
brcmf_btcoex_detach | brcmf_btcoex_timerfunc
| bt_local->timer_on = false;
if (cfg->btcoex->timer_on) |
... |
cancel_work_sync(); |
... |
kfree(cfg->btcoex); // FREE |
| schedule_work(&bt_local->work); // USE
Scenario 2: Freed after the worker is scheduled
The brcmf_btcoex_info is freed after the worker has been scheduled
but before or during its execution. In this case, statements within
the brcmf_btcoex_handler() — such as the container_of macro and
subsequent dereferences of the brcmf_btcoex_info object will cause
a use-after-free access. The following timeline illustrates this
scenario:
CPU0 | CPU1
brcmf_btcoex_detach | brcmf_btcoex_timerfunc
| bt_local->timer_on = false;
if (cfg->btcoex->timer_on) |
... |
cancel_work_sync(); |
... | schedule_work(); // Reschedule
|
kfree(cfg->btcoex); // FREE | brcmf_btcoex_handler() // Worker
/* | btci = container_of(....); // USE
The kfree() above could | ...
also occur at any point | btci-> // USE
during the worker's execution|
*/ |
To resolve the race conditions, drop the conditional check and call
timer_shutdown_sync() directly. It can deactivate the timer reliably,
regardless of its current state. Once stopped, the timer_on state is
then set to false.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-19
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: fix use-after-free in cmp_bss()
Following bss_free() quirk introduced in commit 776b3580178f
("cfg80211: track hidden SSID networks properly"), adjust
cfg80211_update_known_bss() to free the last beacon frame
elements only if they're not shared via the corresponding
'hidden_beacon_bss' pointer.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-19
In the Linux kernel, the following vulnerability has been resolved:
tee: fix NULL pointer dereference in tee_shm_put
tee_shm_put have NULL pointer dereference:
__optee_disable_shm_cache -->
shm = reg_pair_to_ptr(...);//shm maybe return NULL
tee_shm_free(shm); -->
tee_shm_put(shm);//crash
Add check in tee_shm_put to fix it.
panic log:
Unable to handle kernel paging request at virtual address 0000000000100cca
Mem abort info:
ESR = 0x0000000096000004
EC = 0x25: DABT (current EL), IL = 32 bits
SET = 0, FnV = 0
EA = 0, S1PTW = 0
FSC = 0x04: level 0 translation fault
Data abort info:
ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000
CM = 0, WnR = 0, TnD = 0, TagAccess = 0
GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0
user pgtable: 4k pages, 48-bit VAs, pgdp=0000002049d07000
[0000000000100cca] pgd=0000000000000000, p4d=0000000000000000
Internal error: Oops: 0000000096000004 [#1] SMP
CPU: 2 PID: 14442 Comm: systemd-sleep Tainted: P OE ------- ----
6.6.0-39-generic #38
Source Version: 938b255f6cb8817c95b0dd5c8c2944acfce94b07
Hardware name: greatwall GW-001Y1A-FTH, BIOS Great Wall BIOS V3.0
10/26/2022
pstate: 80000005 (Nzcv daif -PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : tee_shm_put+0x24/0x188
lr : tee_shm_free+0x14/0x28
sp : ffff001f98f9faf0
x29: ffff001f98f9faf0 x28: ffff0020df543cc0 x27: 0000000000000000
x26: ffff001f811344a0 x25: ffff8000818dac00 x24: ffff800082d8d048
x23: ffff001f850fcd18 x22: 0000000000000001 x21: ffff001f98f9fb88
x20: ffff001f83e76218 x19: ffff001f83e761e0 x18: 000000000000ffff
x17: 303a30303a303030 x16: 0000000000000000 x15: 0000000000000003
x14: 0000000000000001 x13: 0000000000000000 x12: 0101010101010101
x11: 0000000000000001 x10: 0000000000000001 x9 : ffff800080e08d0c
x8 : ffff001f98f9fb88 x7 : 0000000000000000 x6 : 0000000000000000
x5 : 0000000000000000 x4 : 0000000000000000 x3 : 0000000000000000
x2 : ffff001f83e761e0 x1 : 00000000ffff001f x0 : 0000000000100cca
Call trace:
tee_shm_put+0x24/0x188
tee_shm_free+0x14/0x28
__optee_disable_shm_cache+0xa8/0x108
optee_shutdown+0x28/0x38
platform_shutdown+0x28/0x40
device_shutdown+0x144/0x2b0
kernel_power_off+0x3c/0x80
hibernate+0x35c/0x388
state_store+0x64/0x80
kobj_attr_store+0x14/0x28
sysfs_kf_write+0x48/0x60
kernfs_fop_write_iter+0x128/0x1c0
vfs_write+0x270/0x370
ksys_write+0x6c/0x100
__arm64_sys_write+0x20/0x30
invoke_syscall+0x4c/0x120
el0_svc_common.constprop.0+0x44/0xf0
do_el0_svc+0x24/0x38
el0_svc+0x24/0x88
el0t_64_sync_handler+0x134/0x150
el0t_64_sync+0x14c/0x15
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-19
In the Linux kernel, the following vulnerability has been resolved:
fs: writeback: fix use-after-free in __mark_inode_dirty()
An use-after-free issue occurred when __mark_inode_dirty() get the
bdi_writeback that was in the progress of switching.
CPU: 1 PID: 562 Comm: systemd-random- Not tainted 6.6.56-gb4403bd46a8e #1
......
pstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)
pc : __mark_inode_dirty+0x124/0x418
lr : __mark_inode_dirty+0x118/0x418
sp : ffffffc08c9dbbc0
........
Call trace:
__mark_inode_dirty+0x124/0x418
generic_update_time+0x4c/0x60
file_modified+0xcc/0xd0
ext4_buffered_write_iter+0x58/0x124
ext4_file_write_iter+0x54/0x704
vfs_write+0x1c0/0x308
ksys_write+0x74/0x10c
__arm64_sys_write+0x1c/0x28
invoke_syscall+0x48/0x114
el0_svc_common.constprop.0+0xc0/0xe0
do_el0_svc+0x1c/0x28
el0_svc+0x40/0xe4
el0t_64_sync_handler+0x120/0x12c
el0t_64_sync+0x194/0x198
Root cause is:
systemd-random-seed kworker
----------------------------------------------------------------------
___mark_inode_dirty inode_switch_wbs_work_fn
spin_lock(&inode->i_lock);
inode_attach_wb
locked_inode_to_wb_and_lock_list
get inode->i_wb
spin_unlock(&inode->i_lock);
spin_lock(&wb->list_lock)
spin_lock(&inode->i_lock)
inode_io_list_move_locked
spin_unlock(&wb->list_lock)
spin_unlock(&inode->i_lock)
spin_lock(&old_wb->list_lock)
inode_do_switch_wbs
spin_lock(&inode->i_lock)
inode->i_wb = new_wb
spin_unlock(&inode->i_lock)
spin_unlock(&old_wb->list_lock)
wb_put_many(old_wb, nr_switched)
cgwb_release
old wb released
wb_wakeup_delayed() accesses wb,
then trigger the use-after-free
issue
Fix this race condition by holding inode spinlock until
wb_wakeup_delayed() finished.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-19
In the Linux kernel, the following vulnerability has been resolved:
i40e: Fix potential invalid access when MAC list is empty
list_first_entry() never returns NULL - if the list is empty, it still
returns a pointer to an invalid object, leading to potential invalid
memory access when dereferenced.
Fix this by using list_first_entry_or_null instead of list_first_entry.
CVSS Score
7.1
EPSS Score
0.0
Published
2025-09-19
In the Linux kernel, the following vulnerability has been resolved:
ptp: ocp: fix use-after-free bugs causing by ptp_ocp_watchdog
The ptp_ocp_detach() only shuts down the watchdog timer if it is
pending. However, if the timer handler is already running, the
timer_delete_sync() is not called. This leads to race conditions
where the devlink that contains the ptp_ocp is deallocated while
the timer handler is still accessing it, resulting in use-after-free
bugs. The following details one of the race scenarios.
(thread 1) | (thread 2)
ptp_ocp_remove() |
ptp_ocp_detach() | ptp_ocp_watchdog()
if (timer_pending(&bp->watchdog))| bp = timer_container_of()
timer_delete_sync() |
|
devlink_free(devlink) //free |
| bp-> //use
Resolve this by unconditionally calling timer_delete_sync() to ensure
the timer is reliably deactivated, preventing any access after free.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-19