Linux: >> Linux Kernel >> 6.18.35 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
drivers/base/memory: set mem->altmap after successful device registration
If __add_memory_block() fails at xa_store() (under memory pressure for
example), device_unregister() is called, which eventually triggers
memory_block_release() with mem->altmap still set, causing a
WARN_ON(mem->altmap). This was triggered by modifying virtio-mem driver.
Fix this by delaying the assignment of mem->altmap until after
__add_memory_block() has succeeded.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
fbdev: modedb: fix a possible UAF in fb_find_mode()
If mode_option is NULL, it is assigned from mode_option_buf:
if (!mode_option) {
fb_get_options(NULL, &mode_option_buf);
mode_option = mode_option_buf;
}
Later, name is assigned from mode_option:
const char *name = mode_option;
However, mode_option_buf is freed before name is no longer used:
kfree(mode_option_buf);
while name is still accessed by:
if ((name_matches(db[i], name, namelen) ||
Since name aliases mode_option_buf, this may result in a
use-after-free.
Fix this by extending the lifetime of mode_option_buf until the end of the
function by using scope-based resource management for cleanup.
CVSS Score
7.8
EPSS Score
0.002
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
ACPI: driver: Check ACPI_COMPANION() against NULL during probe
Since every platform driver can be forced to match a device that doesn't
match its list of device IDs because of device_match_driver_override(),
platform drivers that rely on the existence of a device's ACPI companion
object should verify its presence.
Accordingly, add requisite ACPI_COMPANION() or ACPI_HANDLE() checks
against NULL to 13 platform drivers handling core ACPI devices.
Also change the value returned by the ACPI thermal zone driver when
the device's ACPI companion is not present to -ENODEV for consistency
with the other drivers.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5e: xsk: Fix unlocked writing to ICOSQ
During napi poll, when the affinity changes and there's still XSK work
to be done, we trigger an ICOSQ interrupt on the new CPU. However, this
triggering on the ICOSQ is done unprotected.
There are 2 such races:
A) mlx5e_trigger_irq() is called while mlx5e_xsk_alloc_rx_mpwqe() is
running from a different CPU due to affinity change. This can happen
because IRQ triggering is done after napi_complete_done(). At this point
the NAPI can be scheduled on a different CPU. Like this:
CPU A (old affinity, NAPI tail) CPU B (new affinity, fresh NAPI)
------------------------------- --------------------------------
napi_complete_done() clears SCHED
mlx5e_cq_arm(...)
napi_schedule_prep() sets SCHED
mlx5e_napi_poll()
mlx5e_xsk_alloc_rx_mpwqe()
mlx5e_icosq_sync_lock() // noop
memcpy 640 B UMR body
advance sq->pc by 10
mlx5e_trigger_irq(&c->icosq)
wqe_info[pi] = {NOP, 1}
mlx5e_post_nop() advances sq->pc
B) mlx5e_trigger_irq() is called on the ICOSQ when
mlx5e_trigger_napi_icosq() is running.
The obvious fix would be to lock the ICOSQ. But ICOSQ has an optimized
locking scheme that doesn't work for this scenario. Kick the async ICOSQ
instead which is always locked.
This issue was noticed in the wild with the following splat:
netdevice: ge-0-0-1: Bad OP in ICOSQ CQE: 0xd
WARNING: drivers/net/ethernet/mellanox/mlx5/core/en_rx.c:826 [...]
[...]
Call Trace:
<IRQ>
mlx5e_napi_poll+0x11d/0x7f0 [mlx5_core]
__napi_poll+0x30/0x200
? skb_defer_free_flush+0x9c/0xc0
net_rx_action+0x2fe/0x3f0
handle_softirqs+0xd8/0x340
__irq_exit_rcu+0xbc/0xe0
common_interrupt+0x85/0xa0
</IRQ>
<TASK>
asm_common_interrupt+0x26/0x40
[...]
---[ end trace 0000000000000000 ]---
mlx5_core 0000:08:00.0 ge-0-0-1: Error cqe on cqn 0x548, ci 0x2022, qn 0x8f4,
opcode 0xd, syndrome 0x2, vendor syndrome 0x68
00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000030: 00 00 00 00 01 00 68 02 01 00 08 f4 de 14 59 d2
WQE DUMP: WQ size 16384 WQ cur size 0, WQE index 0x1e14, len: 64
00000000: 00 00 00 01 d9 ed 80 02 00 00 00 01 d9 ed 90 02
00000010: 00 00 00 01 d9 ed a0 02 00 00 00 01 d9 ed b0 02
00000020: 00 00 00 01 d9 ed c0 02 00 00 00 01 d9 ed d0 02
00000030: 00 00 00 01 d9 ed e0 02 00 00 00 01 d9 ed f0 02
mlx5_core 0000:08:00.0 ge-0-0-1: Error cqe on cqn 0x548, ci 0x2023, qn 0x8f4,
opcode 0xd, syndrome 0x5, vendor syndrome 0xf9
00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
00000030: 00 00 00 00 01 00 f9 05 01 00 08 f4 de 15 cf d2
CVSS Score
7.5
EPSS Score
0.003
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
xfs: resample the data fork mapping after cycling ILOCK
xfs_reflink_fill_{cow_hole,delalloc} are both presented with an inode,
a data fork mapping, and a cow fork mapping. Unfortunately, these two
helpers cycle the ILOCK to grab a transaction, which means that the
mappings are stale as soon as we reacquire the ILOCK. Currently we
refresh the cow fork mapping by re-calling xfs_find_trim_cow_extent, but
we don't refresh the data fork mapping beforehand, which means that the
xfs_bmap_trim_cow in that function queries the refcount btree about the
wrong physical blocks and returns an inaccurate value in *shared.
If *shared is now false, the directio write proceeds with a stale data
fork mapping. Fix this by querying the data fork mapping if the
sequence counter changes across the ILOCK cycle.
CVSS Score
7.8
EPSS Score
0.005
Published
2026-07-23
In the Linux kernel, the following vulnerability has been resolved:
i2c: stub: Reject I2C block transfers with invalid length
The I2C_SMBUS_I2C_BLOCK_DATA case in stub_xfer() uses data->block[0]
as the transfer length. The existing check only clamps it to avoid
overrunning the chip->words[256] register array, but does not validate
it against I2C_SMBUS_BLOCK_MAX (32), which is the limit of the union
i2c_smbus_data.block buffer (34 bytes total). The driver is a
development/test tool (CONFIG_I2C_STUB=m, not built by default)
that must be loaded with a chip_addr= parameter.
A local user with access to /dev/i2c-* can issue an I2C_SMBUS ioctl
with I2C_SMBUS_I2C_BLOCK_DATA and data->block[0] > 32, causing
stub_xfer() to read or write past the end of the union
i2c_smbus_data.block buffer:
BUG: KASAN: stack-out-of-bounds in stub_xfer (drivers/i2c/i2c-stub.c:223)
Read of size 1 at addr ffff88800abcfd92 by task exploit/81
Call Trace:
<TASK>
stub_xfer (drivers/i2c/i2c-stub.c:223)
__i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:593)
i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:536)
i2cdev_ioctl_smbus (drivers/i2c/i2c-dev.c:391)
i2cdev_ioctl (drivers/i2c/i2c-dev.c:478)
__x64_sys_ioctl (fs/ioctl.c:583)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
</TASK>
The bug exists because i2c-stub implements .smbus_xfer directly,
bypassing the I2C_SMBUS_BLOCK_MAX validation in
i2c_smbus_xfer_emulated(). The I2C_SMBUS_BLOCK_DATA case in the same
function correctly validates against I2C_SMBUS_BLOCK_MAX, but the
I2C_SMBUS_I2C_BLOCK_DATA case does not.
Fix by rejecting transfers with data->block[0] == 0 or
data->block[0] > I2C_SMBUS_BLOCK_MAX with -EINVAL, consistent with
both the I2C_SMBUS_BLOCK_DATA case in the same function and the
I2C_SMBUS_I2C_BLOCK_DATA validation in i2c_smbus_xfer_emulated().
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-20
In the Linux kernel, the following vulnerability has been resolved:
bpf: Reject BPF_MAP_TYPE_INODE_STORAGE creation if BPF LSM is uninitialized
When CONFIG_BPF_LSM=y is set, BPF inode storage maps
(BPF_MAP_TYPE_INODE_STORAGE) are compiled into the kernel. However,
if the BPF LSM is not explicitly enabled at boot time (e.g. omitted
from the "lsm=" boot parameter), lsm_prepare() is never executed for
the BPF LSM.
Consequently, the BPF inode security blob offset
(bpf_lsm_blob_sizes.lbs_inode) is never initialized and remains at
its default compiled size of 8 bytes instead of being updated to a
valid offset past the reserved struct rcu_head (typically 16 bytes
or more).
When a privileged user creates and updates a BPF_MAP_TYPE_INODE_STORAGE
map, bpf_inode() evaluates inode->i_security + 8. This erroneously
aliases the struct rcu_head.func callback pointer at the beginning
of the inode->i_security blob. During subsequent map element cleanup
or inode destruction, writing NULL to owner_storage clears the queued
RCU callback pointer. When rcu_do_batch() later executes the queued
callback, it attempts an instruction fetch at address 0x0, triggering
an immediate kernel panic.
Fix this by introducing a global bpf_lsm_initialized boolean flag
marked with __ro_after_init. Set this flag to true inside bpf_lsm_init()
when the LSM framework successfully registers the BPF LSM. Gate map
allocation in inode_storage_map_alloc() on this flag, returning
-EOPNOTSUPP if the BPF LSM is in turn uninitialized.
This fail-fast approach prevents userspace from allocating inode
storage maps when the supporting BPF LSM infrastructure is absent,
avoiding zombie map states.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-20
In the Linux kernel, the following vulnerability has been resolved:
i2c: i801: fix hardware state machine corruption in error path
A severe livelock and subsequent Hung Task panic were observed in the
i2c-i801 driver during concurrent Fuzzing. The crash is caused by an
unconditional hardware register cleanup in the error handling path of
i801_access().
When i801_check_pre() fails (e.g., returning -EBUSY because the SMBus
controller is actively used by BIOS/ACPI), the kernel does not actually
acquire the hardware ownership. However, the code jumps to the 'out'
label and executes:
iowrite8(SMBHSTSTS_INUSE_STS | STATUS_FLAGS, SMBHSTSTS(priv));
This forcefully clears the INUSE_STS lock and resets the hardware status
flags without owning the controller. Doing so interrupts ongoing BIOS/ACPI
transactions and totally corrupts the SMBus hardware state machine.
Consequently, all subsequent i801_access() calls fail at the pre-check
stage, triggering an endless stream of "SMBus is busy, can't use it!"
error logs. Over a slow serial console, this printk flood monopolizes
the CPU (Console Livelock), starving other processes trying to acquire
the mmap_lock down_read semaphore, ultimately triggering the hung task
watchdog.
Fix this by moving the 'out' label below the hardware register cleanup.
If i801_check_pre() fails, we safely bypass the iowrite8() and only
release the software locks (pm_runtime and mutex), strictly adhering to
the rule of not releasing resources that were never acquired.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-20
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: cancel pending_rx_work before taking conn->lock
l2cap_conn_del() takes conn->lock and then calls cancel_work_sync() for
pending_rx_work. process_pending_rx() takes the same mutex, so teardown
can deadlock against the worker it is flushing.
This issue was found by our static analysis tool and then manually
reviewed against the current tree.
The grounded PoC kept the l2cap_conn_ready() -> queue_work(...,
&conn->pending_rx_work) submit path, the l2cap_conn_del() ->
cancel_work_sync(&conn->pending_rx_work) teardown path, and the
process_pending_rx() -> mutex_lock(&conn->lock) worker edge. Lockdep
WARNING: possible circular locking dependency detected
process_pending_rx+0x21/0x2a [vuln_msv]
l2cap_conn_del.constprop.0+0x3f/0x4e [vuln_msv]
*** DEADLOCK ***
Cancel pending_rx_work before taking conn->lock, matching the existing
lock-before-drain ordering used for the two delayed works in the same
teardown path. The pending_rx queue is still purged after the work has
been cancelled and conn->lock has been acquired.
CVSS Score
8.8
EPSS Score
0.003
Published
2026-07-20
In the Linux kernel, the following vulnerability has been resolved:
net/sched: dualpi2: fix GSO backlog accounting
When DualPI2 splits a GSO skb into N segments, it propagates N
additional packets to its parent before returning NET_XMIT_SUCCESS.
The parent then accounts for the original skb once more, leaving its
qlen one larger than the number of packets actually queued.
With QFQ as the parent, after all real packets are dequeued, QFQ still
has a non-zero qlen while its in-service aggregate has no active
classes. qfq_choose_next_agg() returns NULL and qfq_dequeue() passes
the result to qfq_peek_skb(), causing a NULL pointer dereference.
Follow the same pattern used by tbf_segment() and taprio: count only
successfully queued segments, propagate the difference between the
original skb and those segments, and return NET_XMIT_SUCCESS whenever
at least one segment was queued.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-20