Linux: >> Linux Kernel >> 4.19.264 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_conntrack_helper: pass helper to expect cleanup
nf_conntrack_helper_unregister() calls nf_ct_expect_iterate_destroy()
to remove expectations belonging to the helper being unregistered.
However, it passes NULL instead of the helper pointer as the data
argument, so expect_iter_me() never matches any expectation and all
of them survive the cleanup.
After unregister returns, nfnl_cthelper_del() frees the helper
object immediately. Subsequent expectation dumps or packet-driven
init_conntrack() calls then dereference the freed exp->helper,
causing a use-after-free.
Pass the actual helper pointer so expectations referencing it are
properly destroyed before the helper object is freed.
BUG: KASAN: slab-use-after-free in string+0x38f/0x430
Read of size 1 at addr ffff888003b14d20 by task poc/103
Call Trace:
string+0x38f/0x430
vsnprintf+0x3cc/0x1170
seq_printf+0x17a/0x240
exp_seq_show+0x2e5/0x560
seq_read_iter+0x419/0x1280
proc_reg_read+0x1ac/0x270
vfs_read+0x179/0x930
ksys_read+0xef/0x1c0
Freed by task 103:
The buggy address is located 32 bytes inside of
freed 192-byte region [ffff888003b14d00, ffff888003b14dc0)
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
netfilter: x_tables: ensure names are nul-terminated
Reject names that lack a \0 character before feeding them
to functions that expect c-strings.
Fixes tag is the most recent commit that needs this change.
CVSS Score
7.1
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
crypto: authencesn - Do not place hiseq at end of dst for out-of-place decryption
When decrypting data that is not in-place (src != dst), there is
no need to save the high-order sequence bits in dst as it could
simply be re-copied from the source.
However, the data to be hashed need to be rearranged accordingly.
Thanks,
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: MGMT: validate LTK enc_size on load
Load Long Term Keys stores the user-provided enc_size and later uses
it to size fixed-size stack operations when replying to LE LTK
requests. An enc_size larger than the 16-byte key buffer can therefore
overflow the reply stack buffer.
Reject oversized enc_size values while validating the management LTK
record so invalid keys never reach the stored key state.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ctnetlink: ignore explicit helper on new expectations
Use the existing master conntrack helper, anything else is not really
supported and it just makes validation more complicated, so just ignore
what helper userspace suggests for this expectation.
This was uncovered when validating CTA_EXPECT_CLASS via different helper
provided by userspace than the existing master conntrack helper:
BUG: KASAN: slab-out-of-bounds in nf_ct_expect_related_report+0x2479/0x27c0
Read of size 4 at addr ffff8880043fe408 by task poc/102
Call Trace:
nf_ct_expect_related_report+0x2479/0x27c0
ctnetlink_create_expect+0x22b/0x3b0
ctnetlink_new_expect+0x4bd/0x5c0
nfnetlink_rcv_msg+0x67a/0x950
netlink_rcv_skb+0x120/0x350
Allowing to read kernel memory bytes off the expectation boundary.
CTA_EXPECT_HELP_NAME is still used to offer the helper name to userspace
via netlink dump.
CVSS Score
7.3
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
net: macb: properly unregister fixed rate clocks
The additional resources allocated with clk_register_fixed_rate() need
to be released with clk_unregister_fixed_rate(), otherwise they are lost.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
net: macb: fix clk handling on PCI glue driver removal
platform_device_unregister() may still want to use the registered clks
during runtime resume callback.
Note that there is a commit d82d5303c4c5 ("net: macb: fix use after free
on rmmod") that addressed the similar problem of clk vs platform device
unregistration but just moved the bug to another place.
Save the pointers to clks into local variables for reuse after platform
device is unregistered.
BUG: KASAN: use-after-free in clk_prepare+0x5a/0x60
Read of size 8 at addr ffff888104f85e00 by task modprobe/597
CPU: 2 PID: 597 Comm: modprobe Not tainted 6.1.164+ #114
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.1-0-g3208b098f51a-prebuilt.qemu.org 04/01/2014
Call Trace:
<TASK>
dump_stack_lvl+0x8d/0xba
print_report+0x17f/0x496
kasan_report+0xd9/0x180
clk_prepare+0x5a/0x60
macb_runtime_resume+0x13d/0x410 [macb]
pm_generic_runtime_resume+0x97/0xd0
__rpm_callback+0xc8/0x4d0
rpm_callback+0xf6/0x230
rpm_resume+0xeeb/0x1a70
__pm_runtime_resume+0xb4/0x170
bus_remove_device+0x2e3/0x4b0
device_del+0x5b3/0xdc0
platform_device_del+0x4e/0x280
platform_device_unregister+0x11/0x50
pci_device_remove+0xae/0x210
device_remove+0xcb/0x180
device_release_driver_internal+0x529/0x770
driver_detach+0xd4/0x1a0
bus_remove_driver+0x135/0x260
driver_unregister+0x72/0xb0
pci_unregister_driver+0x26/0x220
__do_sys_delete_module+0x32e/0x550
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
</TASK>
Allocated by task 519:
kasan_save_stack+0x2c/0x50
kasan_set_track+0x21/0x30
__kasan_kmalloc+0x8e/0x90
__clk_register+0x458/0x2890
clk_hw_register+0x1a/0x60
__clk_hw_register_fixed_rate+0x255/0x410
clk_register_fixed_rate+0x3c/0xa0
macb_probe+0x1d8/0x42e [macb_pci]
local_pci_probe+0xd7/0x190
pci_device_probe+0x252/0x600
really_probe+0x255/0x7f0
__driver_probe_device+0x1ee/0x330
driver_probe_device+0x4c/0x1f0
__driver_attach+0x1df/0x4e0
bus_for_each_dev+0x15d/0x1f0
bus_add_driver+0x486/0x5e0
driver_register+0x23a/0x3d0
do_one_initcall+0xfd/0x4d0
do_init_module+0x18b/0x5a0
load_module+0x5663/0x7950
__do_sys_finit_module+0x101/0x180
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
Freed by task 597:
kasan_save_stack+0x2c/0x50
kasan_set_track+0x21/0x30
kasan_save_free_info+0x2a/0x50
__kasan_slab_free+0x106/0x180
__kmem_cache_free+0xbc/0x320
clk_unregister+0x6de/0x8d0
macb_remove+0x73/0xc0 [macb_pci]
pci_device_remove+0xae/0x210
device_remove+0xcb/0x180
device_release_driver_internal+0x529/0x770
driver_detach+0xd4/0x1a0
bus_remove_driver+0x135/0x260
driver_unregister+0x72/0xb0
pci_unregister_driver+0x26/0x220
__do_sys_delete_module+0x32e/0x550
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x6e/0xd8
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
net/x25: Fix potential double free of skb
When alloc_skb fails in x25_queue_rx_frame it calls kfree_skb(skb) at
line 48 and returns 1 (error).
This error propagates back through the call chain:
x25_queue_rx_frame returns 1
|
v
x25_state3_machine receives the return value 1 and takes the else
branch at line 278, setting queued=0 and returning 0
|
v
x25_process_rx_frame returns queued=0
|
v
x25_backlog_rcv at line 452 sees queued=0 and calls kfree_skb(skb)
again
This would free the same skb twice. Looking at x25_backlog_rcv:
net/x25/x25_in.c:x25_backlog_rcv() {
...
queued = x25_process_rx_frame(sk, skb);
...
if (!queued)
kfree_skb(skb);
}
CVSS Score
9.8
EPSS Score
0.001
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
ALSA: ctxfi: Check the error for index mapping
The ctxfi driver blindly assumed a proper value returned from
daio_device_index(), but it's not always true. Add a proper error
check to deal with the error from the function.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
ALSA: caiaq: fix stack out-of-bounds read in init_card
The loop creates a whitespace-stripped copy of the card shortname
where `len < sizeof(card->id)` is used for the bounds check. Since
sizeof(card->id) is 16 and the local id buffer is also 16 bytes,
writing 16 non-space characters fills the entire buffer,
overwriting the terminating nullbyte.
When this non-null-terminated string is later passed to
snd_card_set_id() -> copy_valid_id_string(), the function scans
forward with `while (*nid && ...)` and reads past the end of the
stack buffer, reading the contents of the stack.
A USB device with a product name containing many non-ASCII, non-space
characters (e.g. multibyte UTF-8) will reliably trigger this as follows:
BUG: KASAN: stack-out-of-bounds in copy_valid_id_string
sound/core/init.c:696 [inline]
BUG: KASAN: stack-out-of-bounds in snd_card_set_id_no_lock+0x698/0x74c
sound/core/init.c:718
The off-by-one has been present since commit bafeee5b1f8d ("ALSA:
snd_usb_caiaq: give better shortname") from June 2009 (v2.6.31-rc1),
which first introduced this whitespace-stripping loop. The original
code never accounted for the null terminator when bounding the copy.
Fix this by changing the loop bound to `sizeof(card->id) - 1`,
ensuring at least one byte remains as the null terminator.
CVSS Score
7.1
EPSS Score
0.0
Published
2026-05-01