Linux: >> Linux Kernel >> 4.8.2 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
can: mcp251x: fix deadlock in error path of mcp251x_open
The mcp251x_open() function call free_irq() in its error path with the
mpc_lock mutex held. But if an interrupt already occurred the
interrupt handler will be waiting for the mpc_lock and free_irq() will
deadlock waiting for the handler to finish.
This issue is similar to the one fixed in commit 7dd9c26bd6cf ("can:
mcp251x: fix deadlock if an interrupt occurs during mcp251x_open") but
for the error path.
To solve this issue move the call to free_irq() after the lock is
released. Setting `priv->force_quit = 1` beforehand ensure that the IRQ
handler will exit right away once it acquired the lock.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
x86/efi: defer freeing of boot services memory
efi_free_boot_services() frees memory occupied by EFI_BOOT_SERVICES_CODE
and EFI_BOOT_SERVICES_DATA using memblock_free_late().
There are two issue with that: memblock_free_late() should be used for
memory allocated with memblock_alloc() while the memory reserved with
memblock_reserve() should be freed with free_reserved_area().
More acutely, with CONFIG_DEFERRED_STRUCT_PAGE_INIT=y
efi_free_boot_services() is called before deferred initialization of the
memory map is complete.
Benjamin Herrenschmidt reports that this causes a leak of ~140MB of
RAM on EC2 t3a.nano instances which only have 512MB or RAM.
If the freed memory resides in the areas that memory map for them is
still uninitialized, they won't be actually freed because
memblock_free_late() calls memblock_free_pages() and the latter skips
uninitialized pages.
Using free_reserved_area() at this point is also problematic because
__free_page() accesses the buddy of the freed page and that again might
end up in uninitialized part of the memory map.
Delaying the entire efi_free_boot_services() could be problematic
because in addition to freeing boot services memory it updates
efi.memmap without any synchronization and that's undesirable late in
boot when there is concurrency.
More robust approach is to only defer freeing of the EFI boot services
memory.
Split efi_free_boot_services() in two. First efi_unmap_boot_services()
collects ranges that should be freed into an array then
efi_free_boot_services() later frees them after deferred init is complete.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: cancel rfkill_block work in wiphy_unregister()
There is a use-after-free error in cfg80211_shutdown_all_interfaces found
by syzkaller:
BUG: KASAN: use-after-free in cfg80211_shutdown_all_interfaces+0x213/0x220
Read of size 8 at addr ffff888112a78d98 by task kworker/0:5/5326
CPU: 0 UID: 0 PID: 5326 Comm: kworker/0:5 Not tainted 6.19.0-rc2 #2 PREEMPT(voluntary)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
Workqueue: events cfg80211_rfkill_block_work
Call Trace:
<TASK>
dump_stack_lvl+0x116/0x1f0
print_report+0xcd/0x630
kasan_report+0xe0/0x110
cfg80211_shutdown_all_interfaces+0x213/0x220
cfg80211_rfkill_block_work+0x1e/0x30
process_one_work+0x9cf/0x1b70
worker_thread+0x6c8/0xf10
kthread+0x3c5/0x780
ret_from_fork+0x56d/0x700
ret_from_fork_asm+0x1a/0x30
</TASK>
The problem arises due to the rfkill_block work is not cancelled when wiphy
is being unregistered. In order to fix the issue cancel the corresponding
work in wiphy_unregister().
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
nfc: nci: free skb on nci_transceive early error paths
nci_transceive() takes ownership of the skb passed by the caller,
but the -EPROTO, -EINVAL, and -EBUSY error paths return without
freeing it.
Due to issues clearing NCI_DATA_EXCHANGE fixed by subsequent changes
the nci/nci_dev selftest hits the error path occasionally in NIPA,
and kmemleak detects leaks:
unreferenced object 0xff11000015ce6a40 (size 640):
comm "nci_dev", pid 3954, jiffies 4295441246
hex dump (first 32 bytes):
6b 6b 6b 6b 00 a4 00 0c 02 e1 03 6b 6b 6b 6b 6b kkkk.......kkkkk
6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b 6b kkkkkkkkkkkkkkkk
backtrace (crc 7c40cc2a):
kmem_cache_alloc_node_noprof+0x492/0x630
__alloc_skb+0x11e/0x5f0
alloc_skb_with_frags+0xc6/0x8f0
sock_alloc_send_pskb+0x326/0x3f0
nfc_alloc_send_skb+0x94/0x1d0
rawsock_sendmsg+0x162/0x4c0
do_syscall_64+0x117/0xfc0
CVSS Score
5.5
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
nfc: nci: complete pending data exchange on device close
In nci_close_device(), complete any pending data exchange before
closing. The data exchange callback (e.g.
rawsock_data_exchange_complete) holds a socket reference.
NIPA occasionally hits this leak:
unreferenced object 0xff1100000f435000 (size 2048):
comm "nci_dev", pid 3954, jiffies 4295441245
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
27 00 01 40 00 00 00 00 00 00 00 00 00 00 00 00 '..@............
backtrace (crc ec2b3c5):
__kmalloc_noprof+0x4db/0x730
sk_prot_alloc.isra.0+0xe4/0x1d0
sk_alloc+0x36/0x760
rawsock_create+0xd1/0x540
nfc_sock_create+0x11f/0x280
__sock_create+0x22d/0x630
__sys_socket+0x115/0x1d0
__x64_sys_socket+0x72/0xd0
do_syscall_64+0x117/0xfc0
entry_SYSCALL_64_after_hwframe+0x4b/0x53
CVSS Score
5.5
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
net: usb: kaweth: validate USB endpoints
The kaweth driver should validate that the device it is probing has the
proper number and types of USB endpoints it is expecting before it binds
to it. If a malicious device were to not have the same urbs the driver
will crash later on when it blindly accesses these endpoints.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
smb: client: Don't log plaintext credentials in cifs_set_cifscreds
When debug logging is enabled, cifs_set_cifscreds() logs the key
payload and exposes the plaintext username and password. Remove the
debug log to avoid exposing credentials.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
can: ems_usb: ems_usb_read_bulk_callback(): check the proper length of a message
When looking at the data in a USB urb, the actual_length is the size of
the buffer passed to the driver, not the transfer_buffer_length which is
set by the driver as the max size of the buffer.
When parsing the messages in ems_usb_read_bulk_callback() properly check
the size both at the beginning of parsing the message to make sure it is
big enough for the expected structure, and at the end of the message to
make sure we don't overflow past the end of the buffer for the next
message.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
net: usb: pegasus: validate USB endpoints
The pegasus driver should validate that the device it is probing has the
proper number and types of USB endpoints it is expecting before it binds
to it. If a malicious device were to not have the same urbs the driver
will crash later on when it blindly accesses these endpoints.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
nfc: pn533: properly drop the usb interface reference on disconnect
When the device is disconnected from the driver, there is a "dangling"
reference count on the usb interface that was grabbed in the probe
callback. Fix this up by properly dropping the reference after we are
done with it.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-03-25