Linux: >> Linux Kernel >> 4.19.256 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
net: add vlan_get_protocol_and_depth() helper
Before blamed commit, pskb_may_pull() was used instead
of skb_header_pointer() in __vlan_get_protocol() and friends.
Few callers depended on skb->head being populated with MAC header,
syzbot caught one of them (skb_mac_gso_segment())
Add vlan_get_protocol_and_depth() to make the intent clearer
and use it where sensible.
This is a more generic fix than commit e9d3f80935b6
("net/af_packet: make sure to pull mac header") which was
dealing with a similar issue.
kernel BUG at include/linux/skbuff.h:2655 !
invalid opcode: 0000 [#1] SMP KASAN
CPU: 0 PID: 1441 Comm: syz-executor199 Not tainted 6.1.24-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 04/14/2023
RIP: 0010:__skb_pull include/linux/skbuff.h:2655 [inline]
RIP: 0010:skb_mac_gso_segment+0x68f/0x6a0 net/core/gro.c:136
Code: fd 48 8b 5c 24 10 44 89 6b 70 48 c7 c7 c0 ae 0d 86 44 89 e6 e8 a1 91 d0 00 48 c7 c7 00 af 0d 86 48 89 de 31 d2 e8 d1 4a e9 ff <0f> 0b 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 55 48 89 e5 41
RSP: 0018:ffffc90001bd7520 EFLAGS: 00010286
RAX: ffffffff8469736a RBX: ffff88810f31dac0 RCX: ffff888115a18b00
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
RBP: ffffc90001bd75e8 R08: ffffffff84697183 R09: fffff5200037adf9
R10: 0000000000000000 R11: dffffc0000000001 R12: 0000000000000012
R13: 000000000000fee5 R14: 0000000000005865 R15: 000000000000fed7
FS: 000055555633f300(0000) GS:ffff8881f6a00000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020000000 CR3: 0000000116fea000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
[<ffffffff847018dd>] __skb_gso_segment+0x32d/0x4c0 net/core/dev.c:3419
[<ffffffff8470398a>] skb_gso_segment include/linux/netdevice.h:4819 [inline]
[<ffffffff8470398a>] validate_xmit_skb+0x3aa/0xee0 net/core/dev.c:3725
[<ffffffff84707042>] __dev_queue_xmit+0x1332/0x3300 net/core/dev.c:4313
[<ffffffff851a9ec7>] dev_queue_xmit+0x17/0x20 include/linux/netdevice.h:3029
[<ffffffff851b4a82>] packet_snd net/packet/af_packet.c:3111 [inline]
[<ffffffff851b4a82>] packet_sendmsg+0x49d2/0x6470 net/packet/af_packet.c:3142
[<ffffffff84669a12>] sock_sendmsg_nosec net/socket.c:716 [inline]
[<ffffffff84669a12>] sock_sendmsg net/socket.c:736 [inline]
[<ffffffff84669a12>] __sys_sendto+0x472/0x5f0 net/socket.c:2139
[<ffffffff84669c75>] __do_sys_sendto net/socket.c:2151 [inline]
[<ffffffff84669c75>] __se_sys_sendto net/socket.c:2147 [inline]
[<ffffffff84669c75>] __x64_sys_sendto+0xe5/0x100 net/socket.c:2147
[<ffffffff8551d40f>] do_syscall_x64 arch/x86/entry/common.c:50 [inline]
[<ffffffff8551d40f>] do_syscall_64+0x2f/0x50 arch/x86/entry/common.c:80
[<ffffffff85600087>] entry_SYSCALL_64_after_hwframe+0x63/0xcd
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
cassini: Fix a memory leak in the error handling path of cas_init_one()
cas_saturn_firmware_init() allocates some memory using vmalloc(). This
memory is freed in the .remove() function but not it the error handling
path of the probe.
Add the missing vfree() to avoid a memory leak, should an error occur.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
scsi: snic: Fix possible memory leak if device_add() fails
If device_add() returns error, the name allocated by dev_set_name() needs
be freed. As the comment of device_add() says, put_device() should be used
to give up the reference in the error path. So fix this by calling
put_device(), then the name can be freed in kobject_cleanp().
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
media: uvcvideo: Handle cameras with invalid descriptors
If the source entity does not contain any pads, do not create a link.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
x86/MCE: Always save CS register on AMD Zen IF Poison errors
The Instruction Fetch (IF) units on current AMD Zen-based systems do not
guarantee a synchronous #MC is delivered for poison consumption errors.
Therefore, MCG_STATUS[EIPV|RIPV] will not be set. However, the
microarchitecture does guarantee that the exception is delivered within
the same context. In other words, the exact rIP is not known, but the
context is known to not have changed.
There is no architecturally-defined method to determine this behavior.
The Code Segment (CS) register is always valid on such IF unit poison
errors regardless of the value of MCG_STATUS[EIPV|RIPV].
Add a quirk to save the CS register for poison consumption from the IF
unit banks.
This is needed to properly determine the context of the error.
Otherwise, the severity grading function will assume the context is
IN_KERNEL due to the m->cs value being 0 (the initialized value). This
leads to unnecessary kernel panics on data poison errors due to the
kernel believing the poison consumption occurred in kernel context.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
media: platform: mediatek: vpu: fix NULL ptr dereference
If pdev is NULL, then it is still dereferenced.
This fixes this smatch warning:
drivers/media/platform/mediatek/vpu/mtk_vpu.c:570 vpu_load_firmware() warn: address of NULL pointer 'pdev'
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
cifs: Fix warning and UAF when destroy the MR list
If the MR allocate failed, the MR recovery work not initialized
and list not cleared. Then will be warning and UAF when release
the MR:
WARNING: CPU: 4 PID: 824 at kernel/workqueue.c:3066 __flush_work.isra.0+0xf7/0x110
CPU: 4 PID: 824 Comm: mount.cifs Not tainted 6.1.0-rc5+ #82
RIP: 0010:__flush_work.isra.0+0xf7/0x110
Call Trace:
<TASK>
__cancel_work_timer+0x2ba/0x2e0
smbd_destroy+0x4e1/0x990
_smbd_get_connection+0x1cbd/0x2110
smbd_get_connection+0x21/0x40
cifs_get_tcp_session+0x8ef/0xda0
mount_get_conns+0x60/0x750
cifs_mount+0x103/0xd00
cifs_smb3_do_mount+0x1dd/0xcb0
smb3_get_tree+0x1d5/0x300
vfs_get_tree+0x41/0xf0
path_mount+0x9b3/0xdd0
__x64_sys_mount+0x190/0x1d0
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
BUG: KASAN: use-after-free in smbd_destroy+0x4fc/0x990
Read of size 8 at addr ffff88810b156a08 by task mount.cifs/824
CPU: 4 PID: 824 Comm: mount.cifs Tainted: G W 6.1.0-rc5+ #82
Call Trace:
dump_stack_lvl+0x34/0x44
print_report+0x171/0x472
kasan_report+0xad/0x130
smbd_destroy+0x4fc/0x990
_smbd_get_connection+0x1cbd/0x2110
smbd_get_connection+0x21/0x40
cifs_get_tcp_session+0x8ef/0xda0
mount_get_conns+0x60/0x750
cifs_mount+0x103/0xd00
cifs_smb3_do_mount+0x1dd/0xcb0
smb3_get_tree+0x1d5/0x300
vfs_get_tree+0x41/0xf0
path_mount+0x9b3/0xdd0
__x64_sys_mount+0x190/0x1d0
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
Allocated by task 824:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
__kasan_kmalloc+0x7a/0x90
_smbd_get_connection+0x1b6f/0x2110
smbd_get_connection+0x21/0x40
cifs_get_tcp_session+0x8ef/0xda0
mount_get_conns+0x60/0x750
cifs_mount+0x103/0xd00
cifs_smb3_do_mount+0x1dd/0xcb0
smb3_get_tree+0x1d5/0x300
vfs_get_tree+0x41/0xf0
path_mount+0x9b3/0xdd0
__x64_sys_mount+0x190/0x1d0
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
Freed by task 824:
kasan_save_stack+0x1e/0x40
kasan_set_track+0x21/0x30
kasan_save_free_info+0x2a/0x40
____kasan_slab_free+0x143/0x1b0
__kmem_cache_free+0xc8/0x330
_smbd_get_connection+0x1c6a/0x2110
smbd_get_connection+0x21/0x40
cifs_get_tcp_session+0x8ef/0xda0
mount_get_conns+0x60/0x750
cifs_mount+0x103/0xd00
cifs_smb3_do_mount+0x1dd/0xcb0
smb3_get_tree+0x1d5/0x300
vfs_get_tree+0x41/0xf0
path_mount+0x9b3/0xdd0
__x64_sys_mount+0x190/0x1d0
do_syscall_64+0x35/0x80
entry_SYSCALL_64_after_hwframe+0x46/0xb0
Let's initialize the MR recovery work before MR allocate to prevent
the warning, remove the MRs from the list to prevent the UAF.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
btrfs: don't check PageError in __extent_writepage
__extent_writepage currenly sets PageError whenever any error happens,
and the also checks for PageError to decide if to call error handling.
This leads to very unclear responsibility for cleaning up on errors.
In the VM and generic writeback helpers the basic idea is that once
I/O is fired off all error handling responsibility is delegated to the
end I/O handler. But if that end I/O handler sets the PageError bit,
and the submitter checks it, the bit could in some cases leak into the
submission context for fast enough I/O.
Fix this by simply not checking PageError and just using the local
ret variable to check for submission errors. This also fundamentally
solves the long problem documented in a comment in __extent_writepage
by never leaking the error bit into the submission context.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_sysfs: Fix attempting to call device_add multiple times
device_add shall not be called multiple times as stated in its
documentation:
'Do not call this routine or device_register() more than once for
any device structure'
Syzkaller reports a bug as follows [1]:
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:33!
invalid opcode: 0000 [#1] PREEMPT SMP KASAN
[...]
Call Trace:
<TASK>
__list_add include/linux/list.h:69 [inline]
list_add_tail include/linux/list.h:102 [inline]
kobj_kset_join lib/kobject.c:164 [inline]
kobject_add_internal+0x18f/0x8f0 lib/kobject.c:214
kobject_add_varg lib/kobject.c:358 [inline]
kobject_add+0x150/0x1c0 lib/kobject.c:410
device_add+0x368/0x1e90 drivers/base/core.c:3452
hci_conn_add_sysfs+0x9b/0x1b0 net/bluetooth/hci_sysfs.c:53
hci_le_cis_estabilished_evt+0x57c/0xae0 net/bluetooth/hci_event.c:6799
hci_le_meta_evt+0x2b8/0x510 net/bluetooth/hci_event.c:7110
hci_event_func net/bluetooth/hci_event.c:7440 [inline]
hci_event_packet+0x63d/0xfd0 net/bluetooth/hci_event.c:7495
hci_rx_work+0xae7/0x1230 net/bluetooth/hci_core.c:4007
process_one_work+0x991/0x1610 kernel/workqueue.c:2289
worker_thread+0x665/0x1080 kernel/workqueue.c:2436
kthread+0x2e4/0x3a0 kernel/kthread.c:376
ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
</TASK>
CVSS Score
7.8
EPSS Score
0.0
Published
2025-09-18
In the Linux kernel, the following vulnerability has been resolved:
rcu: Protect rcu_print_task_exp_stall() ->exp_tasks access
For kernels built with CONFIG_PREEMPT_RCU=y, the following scenario can
result in a NULL-pointer dereference:
CPU1 CPU2
rcu_preempt_deferred_qs_irqrestore rcu_print_task_exp_stall
if (special.b.blocked) READ_ONCE(rnp->exp_tasks) != NULL
raw_spin_lock_rcu_node
np = rcu_next_node_entry(t, rnp)
if (&t->rcu_node_entry == rnp->exp_tasks)
WRITE_ONCE(rnp->exp_tasks, np)
....
raw_spin_unlock_irqrestore_rcu_node
raw_spin_lock_irqsave_rcu_node
t = list_entry(rnp->exp_tasks->prev,
struct task_struct, rcu_node_entry)
(if rnp->exp_tasks is NULL, this
will dereference a NULL pointer)
The problem is that CPU2 accesses the rcu_node structure's->exp_tasks
field without holding the rcu_node structure's ->lock and CPU2 did
not observe CPU1's change to rcu_node structure's ->exp_tasks in time.
Therefore, if CPU1 sets rcu_node structure's->exp_tasks pointer to NULL,
then CPU2 might dereference that NULL pointer.
This commit therefore holds the rcu_node structure's ->lock while
accessing that structure's->exp_tasks field.
[ paulmck: Apply Frederic Weisbecker feedback. ]
CVSS Score
5.5
EPSS Score
0.0
Published
2025-09-18