Linux: >> Linux Kernel >> 4.11.4 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
drm/exynos: vidi: use ctx->lock to protect struct vidi_context member variables related to memory alloc/free
Exynos Virtual Display driver performs memory alloc/free operations
without lock protection, which easily causes concurrency problem.
For example, use-after-free can occur in race scenario like this:
```
CPU0 CPU1 CPU2
---- ---- ----
vidi_connection_ioctl()
if (vidi->connection) // true
drm_edid = drm_edid_alloc(); // alloc drm_edid
...
ctx->raw_edid = drm_edid;
...
drm_mode_getconnector()
drm_helper_probe_single_connector_modes()
vidi_get_modes()
if (ctx->raw_edid) // true
drm_edid_dup(ctx->raw_edid);
if (!drm_edid) // false
...
vidi_connection_ioctl()
if (vidi->connection) // false
drm_edid_free(ctx->raw_edid); // free drm_edid
...
drm_edid_alloc(drm_edid->edid)
kmemdup(edid); // UAF!!
...
```
To prevent these vulns, at least in vidi_context, member variables related
to memory alloc/free should be protected with ctx->lock.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-02-18
In the Linux kernel, the following vulnerability has been resolved:
scsi: qla2xxx: Delay module unload while fabric scan in progress
System crash seen during load/unload test in a loop.
[105954.384919] RBP: ffff914589838dc0 R08: 0000000000000000 R09: 0000000000000086
[105954.384920] R10: 000000000000000f R11: ffffa31240904be5 R12: ffff914605f868e0
[105954.384921] R13: ffff914605f86910 R14: 0000000000008010 R15: 00000000ddb7c000
[105954.384923] FS: 0000000000000000(0000) GS:ffff9163fec40000(0000) knlGS:0000000000000000
[105954.384925] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[105954.384926] CR2: 000055d31ce1d6a0 CR3: 0000000119f5e001 CR4: 0000000000770ee0
[105954.384928] PKRU: 55555554
[105954.384929] Call Trace:
[105954.384931] <IRQ>
[105954.384934] qla24xx_sp_unmap+0x1f3/0x2a0 [qla2xxx]
[105954.384962] ? qla_async_scan_sp_done+0x114/0x1f0 [qla2xxx]
[105954.384980] ? qla24xx_els_ct_entry+0x4de/0x760 [qla2xxx]
[105954.384999] ? __wake_up_common+0x80/0x190
[105954.385004] ? qla24xx_process_response_queue+0xc2/0xaa0 [qla2xxx]
[105954.385023] ? qla24xx_msix_rsp_q+0x44/0xb0 [qla2xxx]
[105954.385040] ? __handle_irq_event_percpu+0x3d/0x190
[105954.385044] ? handle_irq_event+0x58/0xb0
[105954.385046] ? handle_edge_irq+0x93/0x240
[105954.385050] ? __common_interrupt+0x41/0xa0
[105954.385055] ? common_interrupt+0x3e/0xa0
[105954.385060] ? asm_common_interrupt+0x22/0x40
The root cause of this was that there was a free (dma_free_attrs) in the
interrupt context. There was a device discovery/fabric scan in
progress. A module unload was issued which set the UNLOADING flag. As
part of the discovery, after receiving an interrupt a work queue was
scheduled (which involved a work to be queued). Since the UNLOADING
flag is set, the work item was not allocated and the mapped memory had
to be freed. The free occurred in interrupt context leading to system
crash. Delay the driver unload until the fabric scan is complete to
avoid the crash.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-18
In the Linux kernel, the following vulnerability has been resolved:
nilfs2: Fix potential block overflow that cause system hang
When a user executes the FITRIM command, an underflow can occur when
calculating nblocks if end_block is too small. Since nblocks is of
type sector_t, which is u64, a negative nblocks value will become a
very large positive integer. This ultimately leads to the block layer
function __blkdev_issue_discard() taking an excessively long time to
process the bio chain, and the ns_segctor_sem lock remains held for a
long period. This prevents other tasks from acquiring the ns_segctor_sem
lock, resulting in the hang reported by syzbot in [1].
If the ending block is too small, typically if it is smaller than 4KiB
range, depending on the usage of the segment 0, it may be possible to
attempt a discard request beyond the device size causing the hang.
Exiting successfully and assign the discarded size (0 in this case)
to range->len.
Although the start and len values in the user input range are too small,
a conservative strategy is adopted here to safely ignore them, which is
equivalent to a no-op; it will not perform any trimming and will not
throw an error.
[1]
task:segctord state:D stack:28968 pid:6093 tgid:6093 ppid:2 task_flags:0x200040 flags:0x00080000
Call Trace:
rwbase_write_lock+0x3dd/0x750 kernel/locking/rwbase_rt.c:272
nilfs_transaction_lock+0x253/0x4c0 fs/nilfs2/segment.c:357
nilfs_segctor_thread_construct fs/nilfs2/segment.c:2569 [inline]
nilfs_segctor_thread+0x6ec/0xe00 fs/nilfs2/segment.c:2684
[ryusuke: corrected part of the commit message about the consequences]
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-18
In the Linux kernel, the following vulnerability has been resolved:
bonding: annotate data-races around slave->last_rx
slave->last_rx and slave->target_last_arp_rx[...] can be read and written
locklessly. Add READ_ONCE() and WRITE_ONCE() annotations.
syzbot reported:
BUG: KCSAN: data-race in bond_rcv_validate / bond_rcv_validate
write to 0xffff888149f0d428 of 8 bytes by interrupt on cpu 1:
bond_rcv_validate+0x202/0x7a0 drivers/net/bonding/bond_main.c:3335
bond_handle_frame+0xde/0x5e0 drivers/net/bonding/bond_main.c:1533
__netif_receive_skb_core+0x5b1/0x1950 net/core/dev.c:6039
__netif_receive_skb_one_core net/core/dev.c:6150 [inline]
__netif_receive_skb+0x59/0x270 net/core/dev.c:6265
netif_receive_skb_internal net/core/dev.c:6351 [inline]
netif_receive_skb+0x4b/0x2d0 net/core/dev.c:6410
...
write to 0xffff888149f0d428 of 8 bytes by interrupt on cpu 0:
bond_rcv_validate+0x202/0x7a0 drivers/net/bonding/bond_main.c:3335
bond_handle_frame+0xde/0x5e0 drivers/net/bonding/bond_main.c:1533
__netif_receive_skb_core+0x5b1/0x1950 net/core/dev.c:6039
__netif_receive_skb_one_core net/core/dev.c:6150 [inline]
__netif_receive_skb+0x59/0x270 net/core/dev.c:6265
netif_receive_skb_internal net/core/dev.c:6351 [inline]
netif_receive_skb+0x4b/0x2d0 net/core/dev.c:6410
br_netif_receive_skb net/bridge/br_input.c:30 [inline]
NF_HOOK include/linux/netfilter.h:318 [inline]
...
value changed: 0x0000000100005365 -> 0x0000000100005366
CVSS Score
4.7
EPSS Score
0.0
Published
2026-02-18
In the Linux kernel, the following vulnerability has been resolved:
scsi: target: iscsi: Fix use-after-free in iscsit_dec_conn_usage_count()
In iscsit_dec_conn_usage_count(), the function calls complete() while
holding the conn->conn_usage_lock. As soon as complete() is invoked, the
waiter (such as iscsit_close_connection()) may wake up and proceed to free
the iscsit_conn structure.
If the waiter frees the memory before the current thread reaches
spin_unlock_bh(), it results in a KASAN slab-use-after-free as the function
attempts to release a lock within the already-freed connection structure.
Fix this by releasing the spinlock before calling complete().
CVSS Score
7.8
EPSS Score
0.0
Published
2026-02-18
In the Linux kernel, the following vulnerability has been resolved:
md: suspend array while updating raid_disks via sysfs
In raid1_reshape(), freeze_array() is called before modifying the r1bio
memory pool (conf->r1bio_pool) and conf->raid_disks, and
unfreeze_array() is called after the update is completed.
However, freeze_array() only waits until nr_sync_pending and
(nr_pending - nr_queued) of all buckets reaches zero. When an I/O error
occurs, nr_queued is increased and the corresponding r1bio is queued to
either retry_list or bio_end_io_list. As a result, freeze_array() may
unblock before these r1bios are released.
This can lead to a situation where conf->raid_disks and the mempool have
already been updated while queued r1bios, allocated with the old
raid_disks value, are later released. Consequently, free_r1bio() may
access memory out of bounds in put_all_bios() and release r1bios of the
wrong size to the new mempool, potentially causing issues with the
mempool as well.
Since only normal I/O might increase nr_queued while an I/O error occurs,
suspending the array avoids this issue.
Note: Updating raid_disks via ioctl SET_ARRAY_INFO already suspends
the array. Therefore, we suspend the array when updating raid_disks
via sysfs to avoid this issue too.
CVSS Score
5.3
EPSS Score
0.0
Published
2026-02-18
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: don't WARN for connections on invalid channels
It's not clear (to me) how exactly syzbot managed to hit this,
but it seems conceivable that e.g. regulatory changed and has
disabled a channel between scanning (channel is checked to be
usable by cfg80211_get_ies_channel_number) and connecting on
the channel later.
With one scenario that isn't covered elsewhere described above,
the warning isn't good, replace it with a (more informative)
error message.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-18
In the Linux kernel, the following vulnerability has been resolved:
net/sched: cls_u32: use skb_header_pointer_careful()
skb_header_pointer() does not fully validate negative @offset values.
Use skb_header_pointer_careful() instead.
GangMin Kim provided a report and a repro fooling u32_classify():
BUG: KASAN: slab-out-of-bounds in u32_classify+0x1180/0x11b0
net/sched/cls_u32.c:221
CVSS Score
7.1
EPSS Score
0.0
Published
2026-02-14
In the Linux kernel, the following vulnerability has been resolved:
macvlan: fix error recovery in macvlan_common_newlink()
valis provided a nice repro to crash the kernel:
ip link add p1 type veth peer p2
ip link set address 00:00:00:00:00:20 dev p1
ip link set up dev p1
ip link set up dev p2
ip link add mv0 link p2 type macvlan mode source
ip link add invalid% link p2 type macvlan mode source macaddr add 00:00:00:00:00:20
ping -c1 -I p1 1.2.3.4
He also gave a very detailed analysis:
<quote valis>
The issue is triggered when a new macvlan link is created with
MACVLAN_MODE_SOURCE mode and MACVLAN_MACADDR_ADD (or
MACVLAN_MACADDR_SET) parameter, lower device already has a macvlan
port and register_netdevice() called from macvlan_common_newlink()
fails (e.g. because of the invalid link name).
In this case macvlan_hash_add_source is called from
macvlan_change_sources() / macvlan_common_newlink():
This adds a reference to vlan to the port's vlan_source_hash using
macvlan_source_entry.
vlan is a pointer to the priv data of the link that is being created.
When register_netdevice() fails, the error is returned from
macvlan_newlink() to rtnl_newlink_create():
if (ops->newlink)
err = ops->newlink(dev, ¶ms, extack);
else
err = register_netdevice(dev);
if (err < 0) {
free_netdev(dev);
goto out;
}
and free_netdev() is called, causing a kvfree() on the struct
net_device that is still referenced in the source entry attached to
the lower device's macvlan port.
Now all packets sent on the macvlan port with a matching source mac
address will trigger a use-after-free in macvlan_forward_source().
</quote valis>
With all that, my fix is to make sure we call macvlan_flush_sources()
regardless of @create value whenever "goto destroy_macvlan_port;"
path is taken.
Many thanks to valis for following up on this issue.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-02-14
In the Linux kernel, the following vulnerability has been resolved:
scsi: target: iscsi: Fix use-after-free in iscsit_dec_session_usage_count()
In iscsit_dec_session_usage_count(), the function calls complete() while
holding the sess->session_usage_lock. Similar to the connection usage count
logic, the waiter signaled by complete() (e.g., in the session release
path) may wake up and free the iscsit_session structure immediately.
This creates a race condition where the current thread may attempt to
execute spin_unlock_bh() on a session structure that has already been
deallocated, resulting in a KASAN slab-use-after-free.
To resolve this, release the session_usage_lock before calling complete()
to ensure all dereferences of the sess pointer are finished before the
waiter is allowed to proceed with deallocation.
CVSS Score
8.8
EPSS Score
0.0
Published
2026-02-14