Linux: >> Linux Kernel >> 5.1.1 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: fix NULL i_assoc_inode dereference in nilfs_mdt_save_to_shadow_map
The DAT inode's btree node cache (i_assoc_inode) is initialized lazily
during btree operations. However, nilfs_mdt_save_to_shadow_map()
assumes i_assoc_inode is already initialized when copying dirty pages
to the shadow map during GC.
If NILFS_IOCTL_CLEAN_SEGMENTS is called immediately after mount before
any btree operation has occurred on the DAT inode, i_assoc_inode is
NULL leading to a general protection fault.
Fix this by calling nilfs_attach_btree_node_cache() on the DAT inode
in nilfs_dat_read() at mount time, ensuring i_assoc_inode is always
initialized before any GC operation can use it.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
media: as102: fix to not free memory after the device is registered in as102_usb_probe()
In as102_usb driver, the following race condition occurs:
```
CPU0 CPU1
as102_usb_probe()
kzalloc(); // alloc as102_dev_t
....
usb_register_dev();
fd = sys_open("/path/to/dev"); // open as102 fd
....
usb_deregister_dev();
....
kfree(); // free as102_dev_t
....
sys_close(fd);
as102_release() // UAF!!
as102_usb_release()
kfree(); // DFB!!
```
When a USB character device registered with usb_register_dev() is later
unregistered (via usb_deregister_dev() or disconnect), the device node is
removed so new open() calls fail. However, file descriptors that are
already open do not go away immediately: they remain valid until the last
reference is dropped and the driver's .release() is invoked.
In as102, as102_usb_probe() calls usb_register_dev() and then, on an
error path, does usb_deregister_dev() and frees as102_dev_t right away.
If userspace raced a successful open() before the deregistration, that
open FD will later hit as102_release() --> as102_usb_release() and access
or free as102_dev_t again, occur a race to use-after-free and
double-free vuln.
The fix is to never kfree(as102_dev_t) directly once usb_register_dev()
has succeeded. After deregistration, defer freeing memory to .release().
In other words, let release() perform the last kfree when the final open
FD is closed.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
wireguard: device: use exit_rtnl callback instead of manual rtnl_lock in pre_exit
wg_netns_pre_exit() manually acquires rtnl_lock() inside the
pernet .pre_exit callback. This causes a hung task when another
thread holds rtnl_mutex - the cleanup_net workqueue (or the
setup_net failure rollback path) blocks indefinitely in
wg_netns_pre_exit() waiting to acquire the lock.
Convert to .exit_rtnl, introduced in commit 7a60d91c690b ("net:
Add ->exit_rtnl() hook to struct pernet_operations."), where the
framework already holds RTNL and batches all callbacks under a
single rtnl_lock()/rtnl_unlock() pair, eliminating the contention
window.
The rcu_assign_pointer(wg->creating_net, NULL) is safe to move
from .pre_exit to .exit_rtnl (which runs after synchronize_rcu())
because all RCU readers of creating_net either use maybe_get_net()
- which returns NULL for a dying namespace with zero refcount - or
access net->user_ns which remains valid throughout the entire
ops_undo_list sequence.
[ Jason: added __net_exit and __read_mostly annotations that were missing. ]
CVSS Score
5.5
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
bcache: fix cached_dev.sb_bio use-after-free and crash
In our production environment, we have received multiple crash reports
regarding libceph, which have caught our attention:
```
[6888366.280350] Call Trace:
[6888366.280452] blk_update_request+0x14e/0x370
[6888366.280561] blk_mq_end_request+0x1a/0x130
[6888366.280671] rbd_img_handle_request+0x1a0/0x1b0 [rbd]
[6888366.280792] rbd_obj_handle_request+0x32/0x40 [rbd]
[6888366.280903] __complete_request+0x22/0x70 [libceph]
[6888366.281032] osd_dispatch+0x15e/0xb40 [libceph]
[6888366.281164] ? inet_recvmsg+0x5b/0xd0
[6888366.281272] ? ceph_tcp_recvmsg+0x6f/0xa0 [libceph]
[6888366.281405] ceph_con_process_message+0x79/0x140 [libceph]
[6888366.281534] ceph_con_v1_try_read+0x5d7/0xf30 [libceph]
[6888366.281661] ceph_con_workfn+0x329/0x680 [libceph]
```
After analyzing the coredump file, we found that the address of
dc->sb_bio has been freed. We know that cached_dev is only freed when it
is stopped.
Since sb_bio is a part of struct cached_dev, rather than an alloc every
time. If the device is stopped while writing to the superblock, the
released address will be accessed at endio.
This patch hopes to wait for sb_write to complete in cached_dev_free.
It should be noted that we analyzed the cause of the problem, then tell
all details to the QWEN and adopted the modifications it made.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
ALSA: 6fire: fix use-after-free on disconnect
In usb6fire_chip_abort(), the chip struct is allocated as the card's
private data (via snd_card_new with sizeof(struct sfire_chip)). When
snd_card_free_when_closed() is called and no file handles are open, the
card and embedded chip are freed synchronously. The subsequent
chip->card = NULL write then hits freed slab memory.
Call trace:
usb6fire_chip_abort sound/usb/6fire/chip.c:59 [inline]
usb6fire_chip_disconnect+0x348/0x358 sound/usb/6fire/chip.c:182
usb_unbind_interface+0x1a8/0x88c drivers/usb/core/driver.c:458
...
hub_event+0x1a04/0x4518 drivers/usb/core/hub.c:5953
Fix by moving the card lifecycle out of usb6fire_chip_abort() and into
usb6fire_chip_disconnect(). The card pointer is saved in a local
before any teardown, snd_card_disconnect() is called first to prevent
new opens, URBs are aborted while chip is still valid, and
snd_card_free_when_closed() is called last so chip is never accessed
after the card may be freed.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
hwmon: (powerz) Fix use-after-free on USB disconnect
After powerz_disconnect() frees the URB and releases the mutex, a
subsequent powerz_read() call can acquire the mutex and call
powerz_read_data(), which dereferences the freed URB pointer.
Fix by:
- Setting priv->urb to NULL in powerz_disconnect() so that
powerz_read_data() can detect the disconnected state.
- Adding a !priv->urb check at the start of powerz_read_data()
to return -ENODEV on a disconnected device.
- Moving usb_set_intfdata() before hwmon registration so the
disconnect handler can always find the priv pointer.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
pmdomain: bcm: bcm2835-power: Increase ASB control timeout
The bcm2835_asb_control() function uses a tight polling loop to wait
for the ASB bridge to acknowledge a request. During intensive workloads,
this handshake intermittently fails for V3D's master ASB on BCM2711,
resulting in "Failed to disable ASB master for v3d" errors during
runtime PM suspend. As a consequence, the failed power-off leaves V3D in
a broken state, leading to bus faults or system hangs on later accesses.
As the timeout is insufficient in some scenarios, increase the polling
timeout from 1us to 5us, which is still negligible in the context of a
power domain transition. Also, replace the open-coded ktime_get_ns()/
cpu_relax() polling loop with readl_poll_timeout_atomic().
CVSS Score
5.5
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
net: bonding: fix NULL deref in bond_debug_rlb_hash_show
rlb_clear_slave intentionally keeps RLB hash-table entries on
the rx_hashtbl_used_head list with slave set to NULL when no
replacement slave is available. However, bond_debug_rlb_hash_show
visites client_info->slave without checking if it's NULL.
Other used-list iterators in bond_alb.c already handle this NULL-slave
state safely:
- rlb_update_client returns early on !client_info->slave
- rlb_req_update_slave_clients, rlb_clear_slave, and rlb_rebalance
compare slave values before visiting
- lb_req_update_subnet_clients continues if slave is NULL
The following NULL deref crash can be trigger in
bond_debug_rlb_hash_show:
[ 1.289791] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 1.292058] RIP: 0010:bond_debug_rlb_hash_show (drivers/net/bonding/bond_debugfs.c:41)
[ 1.293101] RSP: 0018:ffffc900004a7d00 EFLAGS: 00010286
[ 1.293333] RAX: 0000000000000000 RBX: ffff888102b48200 RCX: ffff888102b48204
[ 1.293631] RDX: ffff888102b48200 RSI: ffffffff839daad5 RDI: ffff888102815078
[ 1.293924] RBP: ffff888102815078 R08: ffff888102b4820e R09: 0000000000000000
[ 1.294267] R10: 0000000000000000 R11: 0000000000000000 R12: ffff888100f929c0
[ 1.294564] R13: ffff888100f92a00 R14: 0000000000000001 R15: ffffc900004a7ed8
[ 1.294864] FS: 0000000001395380(0000) GS:ffff888196e75000(0000) knlGS:0000000000000000
[ 1.295239] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 1.295480] CR2: 0000000000000000 CR3: 0000000102adc004 CR4: 0000000000772ef0
[ 1.295897] Call Trace:
[ 1.296134] seq_read_iter (fs/seq_file.c:231)
[ 1.296341] seq_read (fs/seq_file.c:164)
[ 1.296493] full_proxy_read (fs/debugfs/file.c:378 (discriminator 1))
[ 1.296658] vfs_read (fs/read_write.c:572)
[ 1.296981] ksys_read (fs/read_write.c:717)
[ 1.297132] do_syscall_64 (arch/x86/entry/syscall_64.c:63 (discriminator 1) arch/x86/entry/syscall_64.c:94 (discriminator 1))
[ 1.297325] entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
Add a NULL check and print "(none)" for entries with no assigned slave.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: cancel pmsr_free_wk in cfg80211_pmsr_wdev_down
When the nl80211 socket that originated a PMSR request is
closed, cfg80211_release_pmsr() sets the request's nl_portid
to zero and schedules pmsr_free_wk to process the abort
asynchronously. If the interface is concurrently torn down
before that work runs, cfg80211_pmsr_wdev_down() calls
cfg80211_pmsr_process_abort() directly. However, the already-
scheduled pmsr_free_wk work item remains pending and may run
after the interface has been removed from the driver. This
could cause the driver's abort_pmsr callback to operate on a
torn-down interface, leading to undefined behavior and
potential crashes.
Cancel pmsr_free_wk synchronously in cfg80211_pmsr_wdev_down()
before calling cfg80211_pmsr_process_abort(). This ensures any
pending or in-progress work is drained before interface teardown
proceeds, preventing the work from invoking the driver abort
callback after the interface is gone.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-04-24
In the Linux kernel, the following vulnerability has been resolved:
drm/i915/gt: Check set_default_submission() before deferencing
When the i915 driver firmware binaries are not present, the
set_default_submission pointer is not set. This pointer is
dereferenced during suspend anyways.
Add a check to make sure it is set before dereferencing.
[ 23.289926] PM: suspend entry (deep)
[ 23.293558] Filesystems sync: 0.000 seconds
[ 23.298010] Freezing user space processes
[ 23.302771] Freezing user space processes completed (elapsed 0.000 seconds)
[ 23.309766] OOM killer disabled.
[ 23.313027] Freezing remaining freezable tasks
[ 23.318540] Freezing remaining freezable tasks completed (elapsed 0.001 seconds)
[ 23.342038] serial 00:05: disabled
[ 23.345719] serial 00:02: disabled
[ 23.349342] serial 00:01: disabled
[ 23.353782] sd 0:0:0:0: [sda] Synchronizing SCSI cache
[ 23.358993] sd 1:0:0:0: [sdb] Synchronizing SCSI cache
[ 23.361635] ata1.00: Entering standby power mode
[ 23.368863] ata2.00: Entering standby power mode
[ 23.445187] BUG: kernel NULL pointer dereference, address: 0000000000000000
[ 23.452194] #PF: supervisor instruction fetch in kernel mode
[ 23.457896] #PF: error_code(0x0010) - not-present page
[ 23.463065] PGD 0 P4D 0
[ 23.465640] Oops: Oops: 0010 [#1] SMP NOPTI
[ 23.469869] CPU: 8 UID: 0 PID: 211 Comm: kworker/u48:18 Tainted: G S W 6.19.0-rc4-00020-gf0b9d8eb98df #10 PREEMPT(voluntary)
[ 23.482512] Tainted: [S]=CPU_OUT_OF_SPEC, [W]=WARN
[ 23.496511] Workqueue: async async_run_entry_fn
[ 23.501087] RIP: 0010:0x0
[ 23.503755] Code: Unable to access opcode bytes at 0xffffffffffffffd6.
[ 23.510324] RSP: 0018:ffffb4a60065fca8 EFLAGS: 00010246
[ 23.515592] RAX: 0000000000000000 RBX: ffff9f428290e000 RCX: 000000000000000f
[ 23.522765] RDX: 0000000000000000 RSI: 0000000000000282 RDI: ffff9f428290e000
[ 23.529937] RBP: ffff9f4282907070 R08: ffff9f4281130428 R09: 00000000ffffffff
[ 23.537111] R10: 0000000000000000 R11: 0000000000000001 R12: ffff9f42829070f8
[ 23.544284] R13: ffff9f4282906028 R14: ffff9f4282900000 R15: ffff9f4282906b68
[ 23.551457] FS: 0000000000000000(0000) GS:ffff9f466b2cf000(0000) knlGS:0000000000000000
[ 23.559588] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 23.565365] CR2: ffffffffffffffd6 CR3: 000000031c230001 CR4: 0000000000f70ef0
[ 23.572539] PKRU: 55555554
[ 23.575281] Call Trace:
[ 23.577770] <TASK>
[ 23.579905] intel_engines_reset_default_submission+0x42/0x60
[ 23.585695] __intel_gt_unset_wedged+0x191/0x200
[ 23.590360] intel_gt_unset_wedged+0x20/0x40
[ 23.594675] gt_sanitize+0x15e/0x170
[ 23.598290] i915_gem_suspend_late+0x6b/0x180
[ 23.602692] i915_drm_suspend_late+0x35/0xf0
[ 23.607008] ? __pfx_pci_pm_suspend_late+0x10/0x10
[ 23.611843] dpm_run_callback+0x78/0x1c0
[ 23.615817] device_suspend_late+0xde/0x2e0
[ 23.620037] async_suspend_late+0x18/0x30
[ 23.624082] async_run_entry_fn+0x25/0xa0
[ 23.628129] process_one_work+0x15b/0x380
[ 23.632182] worker_thread+0x2a5/0x3c0
[ 23.635973] ? __pfx_worker_thread+0x10/0x10
[ 23.640279] kthread+0xf6/0x1f0
[ 23.643464] ? __pfx_kthread+0x10/0x10
[ 23.647263] ? __pfx_kthread+0x10/0x10
[ 23.651045] ret_from_fork+0x131/0x190
[ 23.654837] ? __pfx_kthread+0x10/0x10
[ 23.658634] ret_from_fork_asm+0x1a/0x30
[ 23.662597] </TASK>
[ 23.664826] Modules linked in:
[ 23.667914] CR2: 0000000000000000
[ 23.671271] ------------[ cut here ]------------
(cherry picked from commit daa199abc3d3d1740c9e3a2c3e9216ae5b447cad)
CVSS Score
5.5
EPSS Score
0.0
Published
2026-04-24