Linux: >> Linux Kernel >> 6.18.34 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/sysfs-schemes: delete tried region in regions_rmdirs()
DAMON sysfs maintains the DAMOS tried region directory objects via a
linked list. When the user requests refresh of the directories, DAMON
sysfs removes all the region directories first, and then generate updated
regions directory on the empty space. The removal function
(damon_sysfs_scheme_regions_rm_dirs()) only puts the kobj objects.
Deletion of the container region object from the linked list is done
inside the kobj release callback function.
If somehow the callback invocation is delayed, the list will contain
regions list that gonna be freed. If the updated region directories
creation is started in this situation, the list can be corrupted and
use-after-free can happen.
Because the kobj objects are managed by only DAMON sysfs, the issue cannot
happen in normal situation. But, such delays can be made on kernels that
built with CONFIG_DEBUG_KOBJECT_RELEASE. On the kernel, the issue can
indeed be reproduced like below.
# damo start --damos_action stat
# cd /sys/kernel/mm/damon/admin/kdamonds/0/
# for i in {1..10}; do echo update_schemes_tried_regions > state; done
# dmesg | grep underflow
[ 89.296152] refcount_t: underflow; use-after-free.
Fix the issue by removing the region object from the list when
decrementing the reference count.
Also update damos_sysfs_populate_region_dir() to add the region object to
the list only after the kobject_init_and_add() is success, so that fail of
kobject_init_and_add() is not leaving the deallocated object on the list.
The issue was discovered [1] by Sashiko.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
media: rc: igorplugusb: fix control request setup packet
Commit eac69475b01f ("media: rc: igorplugusb: heed coherency
rules") changed the control request storage from an embedded struct to
an allocated pointer so it can obey DMA coherency rules.
However, the driver still passes &ir->request to usb_fill_control_urb().
That points the URB setup packet at the pointer field itself rather than
at the allocated struct usb_ctrlrequest.
USB core then interprets pointer bytes as the setup packet. This can
produce an invalid bRequestType and trigger the control direction warning
reported by syzbot:
usb 2-1: BOGUS control dir, pipe 80003580 doesn't match bRequestType 0
Pass ir->request itself as the setup packet.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
gpio: rockchip: teardown bugs and resource leaks
Address several teardown issues and resource leaks in the driver's remove
path and error handling:
1. Debounce clock reference leak: The debounce clock (bank->db_clk) is
obtained using of_clk_get() which increments the clock's reference
count, but clk_put() is never called. Register a devm action to
cleanly release it on unbind. Note that of_clk_get(..., 1) remains
necessary over devm_clk_get() because the DT binding does not define
clock-names, precluding name-based lookup.
2. Unregistered chained IRQ handler: The chained IRQ handler is not
disconnected in remove(). If a stray interrupt fires after the driver
is removed, the kernel attempts to execute a stale handler, leading
to a panic. Fix this by clearing the handler in remove().
3. IRQ domain leak: The linear IRQ domain and its generic chips are
allocated manually during probe but never removed. Remove the IRQ
domain during driver teardown to free the associated generic chips
and mappings.
[Bartosz: don't emit an error message on devres allocation failure]
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: net2280: Fix double free in probe error path
usb_initialize_gadget() installs gadget_release() as the release
callback for the embedded gadget device. The struct net2280 instance is
therefore released through gadget_release() when the gadget device's last
reference is dropped.
The probe error path calls net2280_remove(), which tears down the
partially initialized device and drops the gadget reference with
usb_put_gadget(). Calling kfree(dev) afterwards can free the same object
again.
Drop the explicit kfree() and let the gadget device release callback
handle the final free. This issue was found by a static analysis tool
I am developing.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
ASoC: codecs: simple-mux: Fix enum control bounds check
simple_mux_control_put() rejects values greater than e->items, but
enum control values are zero based. For the two-entry mux used by this
driver, valid values are 0 and 1, so value 2 must be rejected as well.
Accepting e->items can store an invalid mux state, pass it to the GPIO
setter, and pass it on to the DAPM mux update path where it is used as
an index into the enum text array.
Use the same >= e->items check used by the ASoC enum helpers.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-07-24
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:
x86/mm: Disable broadcast TLB flush when PCID is disabled
Booting with "nopcid" clears X86_FEATURE_PCID and keeps CR4.PCIDE from being
set to one. On AMD CPUs that support INVLPGB, broadcast TLB flushing remains
enabled.
There are two checks that decide whether the global ASID code runs,
mm_global_asid() and consider_global_asid(), that key off of the
X86_FEATURE_INVLPGB feature. Once an mm becomes active on more than three
CPUs, consider_global_asid() assigns it a global ASID, after which
flush_tlb_mm_range() takes the broadcast_tlb_flush() path using a non-zero
PCID. Issuing an INVLPGB with a non-zero PCID while CR4.PCIDE is not set
results in a #GP:
Oops: general protection fault, kernel NULL pointer dereference 0x1: 0000 [#1] SMP NOPTI
CPU: 158 UID: 0 PID: 3119 Comm: snap Not tainted 7.1.0-rc3 #1 PREEMPT(full)
Hardware name: ...
RIP: 0010:broadcast_tlb_flush
Code: ... 89 da 48 83 c8 07 <0f> 01 fe eb 08 cc cc cc ...
Call Trace:
<TASK>
flush_tlb_mm_range
ptep_clear_flush
wp_page_copy
? _raw_spin_unlock
__handle_mm_fault
handle_mm_fault
do_user_addr_fault
exc_page_fault
asm_exc_page_fault
All processors that support broadcast TLB invalidation also have PCID support,
so it is only the "nopcid" scenario that is of concern. In this situation just
disable the broadcast TLB support using the CPUID dependency support by making
X86_FEATURE_INVLPGB dependent on X86_FEATURE_PCID.
[ bp: Massage commit message. ]
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: uvc: hold opts->lock across XU walks in uvc_function_bind
uvc_function_bind() walks &opts->extension_units twice without holding
opts->lock:
- directly, for the iExtension string-descriptor fixup loop;
- indirectly, four times via uvc_copy_descriptors() (once per speed),
where the helper iterates uvc->desc.extension_units (which aliases
&opts->extension_units) to size and emit XU descriptors.
The configfs side (uvcg_extension_make / uvcg_extension_drop, in
drivers/usb/gadget/function/uvc_configfs.c) takes opts->lock around its
list_add_tail / list_del operations. A privileged userspace process
that holds the configfs subtree open and writes the gadget UDC name
to bind the function while concurrently rmdir()'ing an extensions
subdir can race uvcg_extension_drop() against the bind-time list walks
and dereference a freed struct uvcg_extension.
Hold opts->lock from the start of the XU string-descriptor fixup
through the last uvc_copy_descriptors() call, releasing on the
descriptor-error path via a new error_unlock label that drops the
lock before falling through to the existing error label. This
matches the locking discipline of the configfs callbacks and removes
the only remaining unsynchronised reader of the XU list during bind.
Reachability: only privileged processes that can mount configfs and
write to gadget UDC files can trigger the race, so this is a
correctness fix rather than a security boundary.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
tty: serial: pch_uart: add check for dma_alloc_coherent()
Add a check for dma_alloc_coherent() failure to prevent a potential
NULL pointer dereference in dma_handle_rx(). Properly release DMA
channels and the PCI device reference using a goto ladder if the
allocation fails.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-24