Linux: >> Linux Kernel >> 3.18.0 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
crypto: af_alg - zero initialize memory allocated via sock_kmalloc
Several crypto user API contexts and requests allocated with
sock_kmalloc() were left uninitialized, relying on callers to
set fields explicitly. This resulted in the use of uninitialized
data in certain error paths or when new fields are added in the
future.
The ACVP patches also contain two user-space interface files:
algif_kpp.c and algif_akcipher.c. These too rely on proper
initialization of their context structures.
A particular issue has been observed with the newly added
'inflight' variable introduced in af_alg_ctx by commit:
67b164a871af ("crypto: af_alg - Disallow multiple in-flight AIO requests")
Because the context is not memset to zero after allocation,
the inflight variable has contained garbage values. As a result,
af_alg_alloc_areq() has incorrectly returned -EBUSY randomly when
the garbage value was interpreted as true:
https://github.com/gregkh/linux/blame/master/crypto/af_alg.c#L1209
The check directly tests ctx->inflight without explicitly
comparing against true/false. Since inflight is only ever set to
true or false later, an uninitialized value has triggered
-EBUSY failures. Zero-initializing memory allocated with
sock_kmalloc() ensures inflight and other fields start in a known
state, removing random issues caused by uninitialized data.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-01-14
In the Linux kernel, the following vulnerability has been resolved:
MIPS: ftrace: Fix memory corruption when kernel is located beyond 32 bits
Since commit e424054000878 ("MIPS: Tracing: Reduce the overhead of
dynamic Function Tracer"), the macro UASM_i_LA_mostly has been used,
and this macro can generate more than 2 instructions. At the same
time, the code in ftrace assumes that no more than 2 instructions can
be generated, which is why it stores them in an int[2] array. However,
as previously noted, the macro UASM_i_LA_mostly (and now UASM_i_LA)
causes a buffer overflow when _mcount is beyond 32 bits. This leads to
corruption of the variables located in the __read_mostly section.
This corruption was observed because the variable
__cpu_primary_thread_mask was corrupted, causing a hang very early
during boot.
This fix prevents the corruption by avoiding the generation of
instructions if they could exceed 2 instructions in
length. Fortunately, insn_la_mcount is only used if the instrumented
code is located outside the kernel code section, so dynamic ftrace can
still be used, albeit in a more limited scope. This is still
preferable to corrupting memory and/or crashing the kernel.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-01-14
In the Linux kernel, the following vulnerability has been resolved:
ip6_gre: make ip6gre_header() robust
Over the years, syzbot found many ways to crash the kernel
in ip6gre_header() [1].
This involves team or bonding drivers ability to dynamically
change their dev->needed_headroom and/or dev->hard_header_len
In this particular crash mld_newpack() allocated an skb
with a too small reserve/headroom, and by the time mld_sendpack()
was called, syzbot managed to attach an ip6gre device.
[1]
skbuff: skb_under_panic: text:ffffffff8a1d69a8 len:136 put:40 head:ffff888059bc7000 data:ffff888059bc6fe8 tail:0x70 end:0x6c0 dev:team0
------------[ cut here ]------------
kernel BUG at net/core/skbuff.c:213 !
<TASK>
skb_under_panic net/core/skbuff.c:223 [inline]
skb_push+0xc3/0xe0 net/core/skbuff.c:2641
ip6gre_header+0xc8/0x790 net/ipv6/ip6_gre.c:1371
dev_hard_header include/linux/netdevice.h:3436 [inline]
neigh_connected_output+0x286/0x460 net/core/neighbour.c:1618
neigh_output include/net/neighbour.h:556 [inline]
ip6_finish_output2+0xfb3/0x1480 net/ipv6/ip6_output.c:136
__ip6_finish_output net/ipv6/ip6_output.c:-1 [inline]
ip6_finish_output+0x234/0x7d0 net/ipv6/ip6_output.c:220
NF_HOOK_COND include/linux/netfilter.h:307 [inline]
ip6_output+0x340/0x550 net/ipv6/ip6_output.c:247
NF_HOOK+0x9e/0x380 include/linux/netfilter.h:318
mld_sendpack+0x8d4/0xe60 net/ipv6/mcast.c:1855
mld_send_cr net/ipv6/mcast.c:2154 [inline]
mld_ifc_work+0x83e/0xd60 net/ipv6/mcast.c:2693
CVSS Score
5.5
EPSS Score
0.001
Published
2026-01-13
In the Linux kernel, the following vulnerability has been resolved:
team: fix check for port enabled in team_queue_override_port_prio_changed()
There has been a syzkaller bug reported recently with the following
trace:
list_del corruption, ffff888058bea080->prev is LIST_POISON2 (dead000000000122)
------------[ cut here ]------------
kernel BUG at lib/list_debug.c:59!
Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI
CPU: 3 UID: 0 PID: 21246 Comm: syz.0.2928 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
RIP: 0010:__list_del_entry_valid_or_report+0x13e/0x200 lib/list_debug.c:59
Code: 48 c7 c7 e0 71 f0 8b e8 30 08 ef fc 90 0f 0b 48 89 ef e8 a5 02 55 fd 48 89 ea 48 89 de 48 c7 c7 40 72 f0 8b e8 13 08 ef fc 90 <0f> 0b 48 89 ef e8 88 02 55 fd 48 89 ea 48 b8 00 00 00 00 00 fc ff
RSP: 0018:ffffc9000d49f370 EFLAGS: 00010286
RAX: 000000000000004e RBX: ffff888058bea080 RCX: ffffc9002817d000
RDX: 0000000000000000 RSI: ffffffff819becc6 RDI: 0000000000000005
RBP: dead000000000122 R08: 0000000000000005 R09: 0000000000000000
R10: 0000000080000000 R11: 0000000000000001 R12: ffff888039e9c230
R13: ffff888058bea088 R14: ffff888058bea080 R15: ffff888055461480
FS: 00007fbbcfe6f6c0(0000) GS:ffff8880d6d0a000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000110c3afcb0 CR3: 00000000382c7000 CR4: 0000000000352ef0
Call Trace:
<TASK>
__list_del_entry_valid include/linux/list.h:132 [inline]
__list_del_entry include/linux/list.h:223 [inline]
list_del_rcu include/linux/rculist.h:178 [inline]
__team_queue_override_port_del drivers/net/team/team_core.c:826 [inline]
__team_queue_override_port_del drivers/net/team/team_core.c:821 [inline]
team_queue_override_port_prio_changed drivers/net/team/team_core.c:883 [inline]
team_priority_option_set+0x171/0x2f0 drivers/net/team/team_core.c:1534
team_option_set drivers/net/team/team_core.c:376 [inline]
team_nl_options_set_doit+0x8ae/0xe60 drivers/net/team/team_core.c:2653
genl_family_rcv_msg_doit+0x209/0x2f0 net/netlink/genetlink.c:1115
genl_family_rcv_msg net/netlink/genetlink.c:1195 [inline]
genl_rcv_msg+0x55c/0x800 net/netlink/genetlink.c:1210
netlink_rcv_skb+0x158/0x420 net/netlink/af_netlink.c:2552
genl_rcv+0x28/0x40 net/netlink/genetlink.c:1219
netlink_unicast_kernel net/netlink/af_netlink.c:1320 [inline]
netlink_unicast+0x5aa/0x870 net/netlink/af_netlink.c:1346
netlink_sendmsg+0x8c8/0xdd0 net/netlink/af_netlink.c:1896
sock_sendmsg_nosec net/socket.c:727 [inline]
__sock_sendmsg net/socket.c:742 [inline]
____sys_sendmsg+0xa98/0xc70 net/socket.c:2630
___sys_sendmsg+0x134/0x1d0 net/socket.c:2684
__sys_sendmsg+0x16d/0x220 net/socket.c:2716
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The problem is in this flow:
1) Port is enabled, queue_id != 0, in qom_list
2) Port gets disabled
-> team_port_disable()
-> team_queue_override_port_del()
-> del (removed from list)
3) Port is disabled, queue_id != 0, not in any list
4) Priority changes
-> team_queue_override_port_prio_changed()
-> checks: port disabled && queue_id != 0
-> calls del - hits the BUG as it is removed already
To fix this, change the check in team_queue_override_port_prio_changed()
so it returns early if port is not enabled.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-01-13
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: btusb: revert use of devm_kzalloc in btusb
This reverts commit 98921dbd00c4e ("Bluetooth: Use devm_kzalloc in
btusb.c file").
In btusb_probe(), we use devm_kzalloc() to allocate the btusb data. This
ties the lifetime of all the btusb data to the binding of a driver to
one interface, INTF. In a driver that binds to other interfaces, ISOC
and DIAG, this is an accident waiting to happen.
The issue is revealed in btusb_disconnect(), where calling
usb_driver_release_interface(&btusb_driver, data->intf) will have devm
free the data that is also being used by the other interfaces of the
driver that may not be released yet.
To fix this, revert the use of devm and go back to freeing memory
explicitly.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-01-13
In the Linux kernel, the following vulnerability has been resolved:
Input: lkkbd - disable pending work before freeing device
lkkbd_interrupt() schedules lk->tq via schedule_work(), and the work
handler lkkbd_reinit() dereferences the lkkbd structure and its
serio/input_dev fields.
lkkbd_disconnect() and error paths in lkkbd_connect() free the lkkbd
structure without preventing the reinit work from being queued again
until serio_close() returns. This can allow the work handler to run
after the structure has been freed, leading to a potential use-after-free.
Use disable_work_sync() instead of cancel_work_sync() to ensure the
reinit work cannot be re-queued, and call it both in lkkbd_disconnect()
and in lkkbd_connect() error paths after serio_open().
CVSS Score
7.8
EPSS Score
0.0
Published
2026-01-13
In the Linux kernel, the following vulnerability has been resolved:
functionfs: fix the open/removal races
ffs_epfile_open() can race with removal, ending up with file->private_data
pointing to freed object.
There is a total count of opened files on functionfs (both ep0 and
dynamic ones) and when it hits zero, dynamic files get removed.
Unfortunately, that removal can happen while another thread is
in ffs_epfile_open(), but has not incremented the count yet.
In that case open will succeed, leaving us with UAF on any subsequent
read() or write().
The root cause is that ffs->opened is misused; atomic_dec_and_test() vs.
atomic_add_return() is not a good idea, when object remains visible all
along.
To untangle that
* serialize openers on ffs->mutex (both for ep0 and for dynamic files)
* have dynamic ones use atomic_inc_not_zero() and fail if we had
zero ->opened; in that case the file we are opening is doomed.
* have the inodes of dynamic files marked on removal (from the
callback of simple_recursive_removal()) - clear ->i_private there.
* have open of dynamic ones verify they hadn't been already removed,
along with checking that state is FFS_ACTIVE.
CVSS Score
4.7
EPSS Score
0.0
Published
2026-01-13
In the Linux kernel, the following vulnerability has been resolved:
scsi: aic94xx: fix use-after-free in device removal path
The asd_pci_remove() function fails to synchronize with pending tasklets
before freeing the asd_ha structure, leading to a potential
use-after-free vulnerability.
When a device removal is triggered (via hot-unplug or module unload),
race condition can occur.
The fix adds tasklet_kill() before freeing the asd_ha structure,
ensuring all scheduled tasklets complete before cleanup proceeds.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-01-13
In the Linux kernel, the following vulnerability has been resolved:
driver core: fix potential null-ptr-deref in device_add()
I got the following null-ptr-deref report while doing fault injection test:
BUG: kernel NULL pointer dereference, address: 0000000000000058
CPU: 2 PID: 278 Comm: 37-i2c-ds2482 Tainted: G B W N 6.1.0-rc3+
RIP: 0010:klist_put+0x2d/0xd0
Call Trace:
<TASK>
klist_remove+0xf1/0x1c0
device_release_driver_internal+0x196/0x210
bus_remove_device+0x1bd/0x240
device_add+0xd3d/0x1100
w1_add_master_device+0x476/0x490 [wire]
ds2482_probe+0x303/0x3e0 [ds2482]
This is how it happened:
w1_alloc_dev()
// The dev->driver is set to w1_master_driver.
memcpy(&dev->dev, device, sizeof(struct device));
device_add()
bus_add_device()
dpm_sysfs_add() // It fails, calls bus_remove_device.
// error path
bus_remove_device()
// The dev->driver is not null, but driver is not bound.
__device_release_driver()
klist_remove(&dev->p->knode_driver) <-- It causes null-ptr-deref.
// normal path
bus_probe_device() // It's not called yet.
device_bind_driver()
If dev->driver is set, in the error path after calling bus_add_device()
in device_add(), bus_remove_device() is called, then the device will be
detached from driver. But device_bind_driver() is not called yet, so it
causes null-ptr-deref while access the 'knode_driver'. To fix this, set
dev->driver to null in the error path before calling bus_remove_device().
CVSS Score
5.5
EPSS Score
0.0
Published
2025-12-30
In the Linux kernel, the following vulnerability has been resolved:
team: Move team device type change at the end of team_port_add
Attempting to add a port device that is already up will expectedly fail,
but not before modifying the team device header_ops.
In the case of the syzbot reproducer the gre0 device is
already in state UP when it attempts to add it as a
port device of team0, this fails but before that
header_ops->create of team0 is changed from eth_header to ipgre_header
in the call to team_dev_type_check_change.
Later when we end up in ipgre_header() struct ip_tunnel* points to nonsense
as the private data of the device still holds a struct team.
Example sequence of iproute2 commands to reproduce the hang/BUG():
ip link add dev team0 type team
ip link add dev gre0 type gre
ip link set dev gre0 up
ip link set dev gre0 master team0
ip link set dev team0 up
ping -I team0 1.1.1.1
Move team_dev_type_check_change down where all other checks have passed
as it changes the dev type with no way to restore it in case
one of the checks that follow it fail.
Also make sure to preserve the origial mtu assignment:
- If port_dev is not the same type as dev, dev takes mtu from port_dev
- If port_dev is the same type as dev, port_dev takes mtu from dev
This is done by adding a conditional before the call to dev_set_mtu
to prevent it from assigning port_dev->mtu = dev->mtu and instead
letting team_dev_type_check_change assign dev->mtu = port_dev->mtu.
The conditional is needed because the patch moves the call to
team_dev_type_check_change past dev_set_mtu.
Testing:
- team device driver in-tree selftests
- Add/remove various devices as slaves of team device
- syzbot
CVSS Score
5.5
EPSS Score
0.0
Published
2025-12-23