Linux: >> Linux Kernel >> 2.6.27.22 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
net/sched: Restrict conditions for adding duplicating netems to qdisc tree
netem_enqueue's duplication prevention logic breaks when a netem
resides in a qdisc tree with other netems - this can lead to a
soft lockup and OOM loop in netem_dequeue, as seen in [1].
Ensure that a duplicating netem cannot exist in a tree with other
netems.
Previous approaches suggested in discussions in chronological order:
1) Track duplication status or ttl in the sk_buff struct. Considered
too specific a use case to extend such a struct, though this would
be a resilient fix and address other previous and potential future
DOS bugs like the one described in loopy fun [2].
2) Restrict netem_enqueue recursion depth like in act_mirred with a
per cpu variable. However, netem_dequeue can call enqueue on its
child, and the depth restriction could be bypassed if the child is a
netem.
3) Use the same approach as in 2, but add metadata in netem_skb_cb
to handle the netem_dequeue case and track a packet's involvement
in duplication. This is an overly complex approach, and Jamal
notes that the skb cb can be overwritten to circumvent this
safeguard.
4) Prevent the addition of a netem to a qdisc tree if its ancestral
path contains a netem. However, filters and actions can cause a
packet to change paths when re-enqueued to the root from netem
duplication, leading us to the current solution: prevent a
duplicating netem from inhabiting the same tree as other netems.
[1] https://lore.kernel.org/netdev/8DuRWwfqjoRDLDmBMlIfbrsZg9Gx50DHJc1ilxsEBNe2D6NMoigR_eIRIG0LOjMc3r10nUUZtArXx4oZBIdUfZQrwjcQhdinnMis_0G7VEk=@willsroot.io/
[2] https://lwn.net/Articles/719297/
CVSS Score
5.5
EPSS Score
0.001
Published
2025-08-19
In the Linux kernel, the following vulnerability has been resolved:
net: appletalk: Fix device refcount leak in atrtr_create()
When updating an existing route entry in atrtr_create(), the old device
reference was not being released before assigning the new device,
leading to a device refcount leak. Fix this by calling dev_put() to
release the old device reference before holding the new one.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
atm: clip: Fix memory leak of struct clip_vcc.
ioctl(ATMARP_MKIP) allocates struct clip_vcc and set it to
vcc->user_back.
The code assumes that vcc_destroy_socket() passes NULL skb
to vcc->push() when the socket is close()d, and then clip_push()
frees clip_vcc.
However, ioctl(ATMARPD_CTRL) sets NULL to vcc->push() in
atm_init_atmarp(), resulting in memory leak.
Let's serialise two ioctl() by lock_sock() and check vcc->push()
in atm_init_atmarp() to prevent memleak.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
iio: common: st_sensors: Fix use of uninitialize device structs
Throughout the various probe functions &indio_dev->dev is used before it
is initialized. This caused a kernel panic in st_sensors_power_enable()
when the call to devm_regulator_bulk_get_enable() fails and then calls
dev_err_probe() with the uninitialized device.
This seems to only cause a panic with dev_err_probe(), dev_err(),
dev_warn() and dev_info() don't seem to cause a panic, but are fixed
as well.
The issue is reported and traced here: [1]
CVSS Score
5.5
EPSS Score
0.0
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
wifi: zd1211rw: Fix potential NULL pointer dereference in zd_mac_tx_to_dev()
There is a potential NULL pointer dereference in zd_mac_tx_to_dev(). For
example, the following is possible:
T0 T1
zd_mac_tx_to_dev()
/* len == skb_queue_len(q) */
while (len > ZD_MAC_MAX_ACK_WAITERS) {
filter_ack()
spin_lock_irqsave(&q->lock, flags);
/* position == skb_queue_len(q) */
for (i=1; i<position; i++)
skb = __skb_dequeue(q)
if (mac->type == NL80211_IFTYPE_AP)
skb = __skb_dequeue(q);
spin_unlock_irqrestore(&q->lock, flags);
skb_dequeue() -> NULL
Since there is a small gap between checking skb queue length and skb being
unconditionally dequeued in zd_mac_tx_to_dev(), skb_dequeue() can return NULL.
Then the pointer is passed to zd_mac_tx_status() where it is dereferenced.
In order to avoid potential NULL pointer dereference due to situations like
above, check if skb is not NULL before passing it to zd_mac_tx_status().
Found by Linux Verification Center (linuxtesting.org) with SVACE.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
do_change_type(): refuse to operate on unmounted/not ours mounts
Ensure that propagation settings can only be changed for mounts located
in the caller's mount namespace. This change aligns permission checking
with the rest of mount(2).
CVSS Score
5.5
EPSS Score
0.0
Published
2025-07-30
In the Linux kernel, the following vulnerability has been resolved:
netlink: Fix wraparounds of sk->sk_rmem_alloc.
Netlink has this pattern in some places
if (atomic_read(&sk->sk_rmem_alloc) > sk->sk_rcvbuf)
atomic_add(skb->truesize, &sk->sk_rmem_alloc);
, which has the same problem fixed by commit 5a465a0da13e ("udp:
Fix multiple wraparounds of sk->sk_rmem_alloc.").
For example, if we set INT_MAX to SO_RCVBUFFORCE, the condition
is always false as the two operands are of int.
Then, a single socket can eat as many skb as possible until OOM
happens, and we can see multiple wraparounds of sk->sk_rmem_alloc.
Let's fix it by using atomic_add_return() and comparing the two
variables as unsigned int.
Before:
[root@fedora ~]# ss -f netlink
Recv-Q Send-Q Local Address:Port Peer Address:Port
-1668710080 0 rtnl:nl_wraparound/293 *
After:
[root@fedora ~]# ss -f netlink
Recv-Q Send-Q Local Address:Port Peer Address:Port
2147483072 0 rtnl:nl_wraparound/290 *
^
`--- INT_MAX - 576
CVSS Score
5.5
EPSS Score
0.0
Published
2025-07-25
In the Linux kernel, the following vulnerability has been resolved:
net/sched: Abort __tc_modify_qdisc if parent class does not exist
Lion's patch [1] revealed an ancient bug in the qdisc API.
Whenever a user creates/modifies a qdisc specifying as a parent another
qdisc, the qdisc API will, during grafting, detect that the user is
not trying to attach to a class and reject. However grafting is
performed after qdisc_create (and thus the qdiscs' init callback) is
executed. In qdiscs that eventually call qdisc_tree_reduce_backlog
during init or change (such as fq, hhf, choke, etc), an issue
arises. For example, executing the following commands:
sudo tc qdisc add dev lo root handle a: htb default 2
sudo tc qdisc add dev lo parent a: handle beef fq
Qdiscs such as fq, hhf, choke, etc unconditionally invoke
qdisc_tree_reduce_backlog() in their control path init() or change() which
then causes a failure to find the child class; however, that does not stop
the unconditional invocation of the assumed child qdisc's qlen_notify with
a null class. All these qdiscs make the assumption that class is non-null.
The solution is ensure that qdisc_leaf() which looks up the parent
class, and is invoked prior to qdisc_create(), should return failure on
not finding the class.
In this patch, we leverage qdisc_leaf to return ERR_PTRs whenever the
parentid doesn't correspond to a class, so that we can detect it
earlier on and abort before qdisc_create is called.
[1] https://lore.kernel.org/netdev/d912cbd7-193b-4269-9857-525bee8bbb6a@gmail.com/
CVSS Score
5.5
EPSS Score
0.0
Published
2025-07-25
In the Linux kernel, the following vulnerability has been resolved:
atm: clip: Fix NULL pointer dereference in vcc_sendmsg()
atmarpd_dev_ops does not implement the send method, which may cause crash
as bellow.
BUG: kernel NULL pointer dereference, address: 0000000000000000
PGD 0 P4D 0
Oops: Oops: 0010 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5324 Comm: syz.0.0 Not tainted 6.15.0-rc6-syzkaller-00346-g5723cc3450bc #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: 0010:0x0
Code: Unable to access opcode bytes at 0xffffffffffffffd6.
RSP: 0018:ffffc9000d3cf778 EFLAGS: 00010246
RAX: 1ffffffff1910dd1 RBX: 00000000000000c0 RCX: dffffc0000000000
RDX: ffffc9000dc82000 RSI: ffff88803e4c4640 RDI: ffff888052cd0000
RBP: ffffc9000d3cf8d0 R08: ffff888052c9143f R09: 1ffff1100a592287
R10: dffffc0000000000 R11: 0000000000000000 R12: 1ffff92001a79f00
R13: ffff888052cd0000 R14: ffff88803e4c4640 R15: ffffffff8c886e88
FS: 00007fbc762566c0(0000) GS:ffff88808d6c2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffffffffd6 CR3: 0000000041f1b000 CR4: 0000000000352ef0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
vcc_sendmsg+0xa10/0xc50 net/atm/common.c:644
sock_sendmsg_nosec net/socket.c:712 [inline]
__sock_sendmsg+0x219/0x270 net/socket.c:727
____sys_sendmsg+0x52d/0x830 net/socket.c:2566
___sys_sendmsg+0x21f/0x2a0 net/socket.c:2620
__sys_sendmmsg+0x227/0x430 net/socket.c:2709
__do_sys_sendmmsg net/socket.c:2736 [inline]
__se_sys_sendmmsg net/socket.c:2733 [inline]
__x64_sys_sendmmsg+0xa0/0xc0 net/socket.c:2733
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xf6/0x210 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
CVSS Score
5.5
EPSS Score
0.0
Published
2025-07-25
In the Linux kernel, the following vulnerability has been resolved:
atm: clip: Fix infinite recursive call of clip_push().
syzbot reported the splat below. [0]
This happens if we call ioctl(ATMARP_MKIP) more than once.
During the first call, clip_mkip() sets clip_push() to vcc->push(),
and the second call copies it to clip_vcc->old_push().
Later, when the socket is close()d, vcc_destroy_socket() passes
NULL skb to clip_push(), which calls clip_vcc->old_push(),
triggering the infinite recursion.
Let's prevent the second ioctl(ATMARP_MKIP) by checking
vcc->user_back, which is allocated by the first call as clip_vcc.
Note also that we use lock_sock() to prevent racy calls.
[0]:
BUG: TASK stack guard page was hit at ffffc9000d66fff8 (stack is ffffc9000d670000..ffffc9000d678000)
Oops: stack guard page: 0000 [#1] SMP KASAN NOPTI
CPU: 0 UID: 0 PID: 5322 Comm: syz.0.0 Not tainted 6.16.0-rc4-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:clip_push+0x5/0x720 net/atm/clip.c:191
Code: e0 8f aa 8c e8 1c ad 5b fa eb ae 66 2e 0f 1f 84 00 00 00 00 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 55 <41> 57 41 56 41 55 41 54 53 48 83 ec 20 48 89 f3 49 89 fd 48 bd 00
RSP: 0018:ffffc9000d670000 EFLAGS: 00010246
RAX: 1ffff1100235a4a5 RBX: ffff888011ad2508 RCX: ffff8880003c0000
RDX: 0000000000000000 RSI: 0000000000000000 RDI: ffff888037f01000
RBP: dffffc0000000000 R08: ffffffff8fa104f7 R09: 1ffffffff1f4209e
R10: dffffc0000000000 R11: ffffffff8a99b300 R12: ffffffff8a99b300
R13: ffff888037f01000 R14: ffff888011ad2500 R15: ffff888037f01578
FS: 000055557ab6d500(0000) GS:ffff88808d250000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffc9000d66fff8 CR3: 0000000043172000 CR4: 0000000000352ef0
Call Trace:
<TASK>
clip_push+0x6dc/0x720 net/atm/clip.c:200
clip_push+0x6dc/0x720 net/atm/clip.c:200
clip_push+0x6dc/0x720 net/atm/clip.c:200
...
clip_push+0x6dc/0x720 net/atm/clip.c:200
clip_push+0x6dc/0x720 net/atm/clip.c:200
clip_push+0x6dc/0x720 net/atm/clip.c:200
vcc_destroy_socket net/atm/common.c:183 [inline]
vcc_release+0x157/0x460 net/atm/common.c:205
__sock_release net/socket.c:647 [inline]
sock_close+0xc0/0x240 net/socket.c:1391
__fput+0x449/0xa70 fs/file_table.c:465
task_work_run+0x1d1/0x260 kernel/task_work.c:227
resume_user_mode_work include/linux/resume_user_mode.h:50 [inline]
exit_to_user_mode_loop+0xec/0x110 kernel/entry/common.c:114
exit_to_user_mode_prepare include/linux/entry-common.h:330 [inline]
syscall_exit_to_user_mode_work include/linux/entry-common.h:414 [inline]
syscall_exit_to_user_mode include/linux/entry-common.h:449 [inline]
do_syscall_64+0x2bd/0x3b0 arch/x86/entry/syscall_64.c:100
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7ff31c98e929
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fffb5aa1f78 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4
RAX: 0000000000000000 RBX: 0000000000012747 RCX: 00007ff31c98e929
RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003
RBP: 00007ff31cbb7ba0 R08: 0000000000000001 R09: 0000000db5aa226f
R10: 00007ff31c7ff030 R11: 0000000000000246 R12: 00007ff31cbb608c
R13: 00007ff31cbb6080 R14: ffffffffffffffff R15: 00007fffb5aa2090
</TASK>
Modules linked in:
CVSS Score
7.8
EPSS Score
0.0
Published
2025-07-25