CVE-2025-40074CRITICAL(9.8)
EPSS 0.4%
In the Linux kernel, the following vulnerability has been resolved:
ipv4: start using dst_dev_rcu()
Change icmpv4_xrlim_allow(), ip_defrag() to prevent possible UAF.
Change ipmr_prepare_xmit(), ipmr_queue_fwd_xmit(), ip_mr_output(),
ipv4_neigh_lookup() to use lockdep enabled dst_dev_rcu().
CVE-2025-40039HIGH(8.8)
EPSS 0.3%
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: Fix race condition in RPC handle list access
The 'sess->rpc_handle_list' XArray manages RPC handles within a ksmbd
session. Access to this list is intended to be protected by
'sess->rpc_lock' (an rw_semaphore). However, the locking implementation was
flawed, leading to potential race conditions.
In ksmbd_session_rpc_open(), the code incorrectly acquired only a read lock
before calling xa_store() and xa_erase(). Since these operations modify
the XArray structure, a write lock is required to ensure exclusive access
and prevent data corruption from concurrent modifications.
Furthermore, ksmbd_session_rpc_method() accessed the list using xa_load()
without holding any lock at all. This could lead to reading inconsistent
data or a potential use-after-free if an entry is concurrently removed and
the pointer is dereferenced.
Fix these issues by:
1. Using down_write() and up_write() in ksmbd_session_rpc_open()
to ensure exclusive access during XArray modification, and ensuring
the lock is correctly released on error paths.
2. Adding down_read() and up_read() in ksmbd_session_rpc_method()
to safely protect the lookup.
CVE-2025-40043HIGH(8.8)
EPSS 0.3%
In the Linux kernel, the following vulnerability has been resolved:
net: nfc: nci: Add parameter validation for packet data
Syzbot reported an uninitialized value bug in nci_init_req, which was
introduced by commit 5aca7966d2a7 ("Merge tag
'perf-tools-fixes-for-v6.17-2025-09-16' of
git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools").
This bug arises due to very limited and poor input validation
that was done at nic_valid_size(). This validation only
validates the skb->len (directly reflects size provided at the
userspace interface) with the length provided in the buffer
itself (interpreted as NCI_HEADER). This leads to the processing
of memory content at the address assuming the correct layout
per what opcode requires there. This leads to the accesses to
buffer of `skb_buff->data` which is not assigned anything yet.
Following the same silent drop of packets of invalid sizes at
`nic_valid_size()`, add validation of the data in the respective
handlers and return error values in case of failure. Release
the skb if error values are returned from handlers in
`nci_nft_packet` and effectively do a silent drop
Possible TODO: because we silently drop the packets, the
call to `nci_request` will be waiting for completion of request
and will face timeouts. These timeouts can get excessively logged
in the dmesg. A proper handling of them may require to export
`nci_request_cancel` (or propagate error handling from the
nft packets handlers).
CVE-2025-40058HIGH(8.8)
EPSS 0.2%
In the Linux kernel, the following vulnerability has been resolved:
iommu/vt-d: Disallow dirty tracking if incoherent page walk
Dirty page tracking relies on the IOMMU atomically updating the dirty bit
in the paging-structure entry. For this operation to succeed, the paging-
structure memory must be coherent between the IOMMU and the CPU. In
another word, if the iommu page walk is incoherent, dirty page tracking
doesn't work.
The Intel VT-d specification, Section 3.10 "Snoop Behavior" states:
"Remapping hardware encountering the need to atomically update A/EA/D bits
in a paging-structure entry that is not snooped will result in a non-
recoverable fault."
To prevent an IOMMU from being incorrectly configured for dirty page
tracking when it is operating in an incoherent mode, mark SSADS as
supported only when both ecap_slads and ecap_smpwc are supported.
CVE-2025-40046HIGH(8.6)
EPSS 0.3%
In the Linux kernel, the following vulnerability has been resolved:
io_uring/zcrx: fix overshooting recv limit
It's reported that sometimes a zcrx request can receive more than was
requested. It's caused by io_zcrx_recv_skb() adjusting desc->count for
all received buffers including frag lists, but then doing recursive
calls to process frag list skbs, which leads to desc->count double
accounting and underflow.
CVE-2025-40068HIGH(8.4)
EPSS 0.2%
In the Linux kernel, the following vulnerability has been resolved:
fs: ntfs3: Fix integer overflow in run_unpack()
The MFT record relative to the file being opened contains its runlist,
an array containing information about the file's location on the physical
disk. Analysis of all Call Stack paths showed that the values of the
runlist array, from which LCNs are calculated, are not validated before
run_unpack function.
The run_unpack function decodes the compressed runlist data format
from MFT attributes (for example, $DATA), converting them into a runs_tree
structure, which describes the mapping of virtual clusters (VCN) to
logical clusters (LCN). The NTFS3 subsystem also has a shortcut for
deleting files from MFT records - in this case, the RUN_DEALLOCATE
command is sent to the run_unpack input, and the function logic
provides that all data transferred to the runlist about file or
directory is deleted without creating a runs_tree structure.
Substituting the runlist in the $DATA attribute of the MFT record for an
arbitrary file can lead either to access to arbitrary data on the disk
bypassing access checks to them (since the inode access check
occurs above) or to destruction of arbitrary data on the disk.
Add overflow check for addition operation.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
CVE-2025-40075HIGH(8.1)
EPSS 0.4%
In the Linux kernel, the following vulnerability has been resolved:
tcp_metrics: use dst_dev_net_rcu()
Replace three dst_dev() with a lockdep enabled helper.
CVE-2025-40040HIGH(7.8)
EPSS 0.4%
In the Linux kernel, the following vulnerability has been resolved:
mm/ksm: fix flag-dropping behavior in ksm_madvise
syzkaller discovered the following crash: (kernel BUG)
[ 44.607039] ------------[ cut here ]------------
[ 44.607422] kernel BUG at mm/userfaultfd.c:2067!
[ 44.608148] Oops: invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC KASAN NOPTI
[ 44.608814] CPU: 1 UID: 0 PID: 2475 Comm: reproducer Not tainted 6.16.0-rc6 #1 PREEMPT(none)
[ 44.609635] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014
[ 44.610695] RIP: 0010:userfaultfd_release_all+0x3a8/0x460
<snip other registers, drop unreliable trace>
[ 44.617726] Call Trace:
[ 44.617926] <TASK>
[ 44.619284] userfaultfd_release+0xef/0x1b0
[ 44.620976] __fput+0x3f9/0xb60
[ 44.621240] fput_close_sync+0x110/0x210
[ 44.622222] __x64_sys_close+0x8f/0x120
[ 44.622530] do_syscall_64+0x5b/0x2f0
[ 44.622840] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 44.623244] RIP: 0033:0x7f365bb3f227
Kernel panics because it detects UFFD inconsistency during
userfaultfd_release_all(). Specifically, a VMA which has a valid pointer
to vma->vm_userfaultfd_ctx, but no UFFD flags in vma->vm_flags.
The inconsistency is caused in ksm_madvise(): when user calls madvise()
with MADV_UNMEARGEABLE on a VMA that is registered for UFFD in MINOR mode,
it accidentally clears all flags stored in the upper 32 bits of
vma->vm_flags.
Assuming x86_64 kernel build, unsigned long is 64-bit and unsigned int and
int are 32-bit wide. This setup causes the following mishap during the &=
~VM_MERGEABLE assignment.
VM_MERGEABLE is a 32-bit constant of type unsigned int, 0x8000'0000.
After ~ is applied, it becomes 0x7fff'ffff unsigned int, which is then
promoted to unsigned long before the & operation. This promotion fills
upper 32 bits with leading 0s, as we're doing unsigned conversion (and
even for a signed conversion, this wouldn't help as the leading bit is 0).
& operation thus ends up AND-ing vm_flags with 0x0000'0000'7fff'ffff
instead of intended 0xffff'ffff'7fff'ffff and hence accidentally clears
the upper 32-bits of its value.
Fix it by changing `VM_MERGEABLE` constant to unsigned long, using the
BIT() macro.
Note: other VM_* flags are not affected: This only happens to the
VM_MERGEABLE flag, as the other VM_* flags are all constants of type int
and after ~ operation, they end up with leading 1 and are thus converted
to unsigned long with leading 1s.
Note 2:
After commit 31defc3b01d9 ("userfaultfd: remove (VM_)BUG_ON()s"), this is
no longer a kernel BUG, but a WARNING at the same place:
[ 45.595973] WARNING: CPU: 1 PID: 2474 at mm/userfaultfd.c:2067
but the root-cause (flag-drop) remains the same.
[akpm@linux-foundation.org: rust bindgen wasn't able to handle BIT(), from Miguel]
CVE-2025-40044HIGH(7.8)
EPSS 0.2%
In the Linux kernel, the following vulnerability has been resolved:
fs: udf: fix OOB read in lengthAllocDescs handling
When parsing Allocation Extent Descriptor, lengthAllocDescs comes from
on-disk data and must be validated against the block size. Crafted or
corrupted images may set lengthAllocDescs so that the total descriptor
length (sizeof(allocExtDesc) + lengthAllocDescs) exceeds the buffer,
leading udf_update_tag() to call crc_itu_t() on out-of-bounds memory and
trigger a KASAN use-after-free read.
BUG: KASAN: use-after-free in crc_itu_t+0x1d5/0x2b0 lib/crc-itu-t.c:60
Read of size 1 at addr ffff888041e7d000 by task syz-executor317/5309
CPU: 0 UID: 0 PID: 5309 Comm: syz-executor317 Not tainted 6.12.0-rc4-syzkaller-00261-g850925a8133c #0
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x241/0x360 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:377 [inline]
print_report+0x169/0x550 mm/kasan/report.c:488
kasan_report+0x143/0x180 mm/kasan/report.c:601
crc_itu_t+0x1d5/0x2b0 lib/crc-itu-t.c:60
udf_update_tag+0x70/0x6a0 fs/udf/misc.c:261
udf_write_aext+0x4d8/0x7b0 fs/udf/inode.c:2179
extent_trunc+0x2f7/0x4a0 fs/udf/truncate.c:46
udf_truncate_tail_extent+0x527/0x7e0 fs/udf/truncate.c:106
udf_release_file+0xc1/0x120 fs/udf/file.c:185
__fput+0x23f/0x880 fs/file_table.c:431
task_work_run+0x24f/0x310 kernel/task_work.c:239
exit_task_work include/linux/task_work.h:43 [inline]
do_exit+0xa2f/0x28e0 kernel/exit.c:939
do_group_exit+0x207/0x2c0 kernel/exit.c:1088
__do_sys_exit_group kernel/exit.c:1099 [inline]
__se_sys_exit_group kernel/exit.c:1097 [inline]
__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1097
x64_sys_call+0x2634/0x2640 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
</TASK>
Validate the computed total length against epos->bh->b_size.
Found by Linux Verification Center (linuxtesting.org) with Syzkaller.
CVE-2025-40054HIGH(7.8)
EPSS 0.2%
In the Linux kernel, the following vulnerability has been resolved:
f2fs: fix UAF issue in f2fs_merge_page_bio()
As JY reported in bugzilla [1],
Unable to handle kernel NULL pointer dereference at virtual address 0000000000000000
pc : [0xffffffe51d249484] f2fs_is_cp_guaranteed+0x70/0x98
lr : [0xffffffe51d24adbc] f2fs_merge_page_bio+0x520/0x6d4
CPU: 3 UID: 0 PID: 6790 Comm: kworker/u16:3 Tainted: P B W OE 6.12.30-android16-5-maybe-dirty-4k #1 5f7701c9cbf727d1eebe77c89bbbeb3371e895e5
Tainted: [P]=PROPRIETARY_MODULE, [B]=BAD_PAGE, [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
Workqueue: writeback wb_workfn (flush-254:49)
Call trace:
f2fs_is_cp_guaranteed+0x70/0x98
f2fs_inplace_write_data+0x174/0x2f4
f2fs_do_write_data_page+0x214/0x81c
f2fs_write_single_data_page+0x28c/0x764
f2fs_write_data_pages+0x78c/0xce4
do_writepages+0xe8/0x2fc
__writeback_single_inode+0x4c/0x4b4
writeback_sb_inodes+0x314/0x540
__writeback_inodes_wb+0xa4/0xf4
wb_writeback+0x160/0x448
wb_workfn+0x2f0/0x5dc
process_scheduled_works+0x1c8/0x458
worker_thread+0x334/0x3f0
kthread+0x118/0x1ac
ret_from_fork+0x10/0x20
[1] https://bugzilla.kernel.org/show_bug.cgi?id=220575
The panic was caused by UAF issue w/ below race condition:
kworker
- writepages
- f2fs_write_cache_pages
- f2fs_write_single_data_page
- f2fs_do_write_data_page
- f2fs_inplace_write_data
- f2fs_merge_page_bio
- add_inu_page
: cache page #1 into bio & cache bio in
io->bio_list
- f2fs_write_single_data_page
- f2fs_do_write_data_page
- f2fs_inplace_write_data
- f2fs_merge_page_bio
- add_inu_page
: cache page #2 into bio which is linked
in io->bio_list
write
- f2fs_write_begin
: write page #1
- f2fs_folio_wait_writeback
- f2fs_submit_merged_ipu_write
- f2fs_submit_write_bio
: submit bio which inclues page #1 and #2
software IRQ
- f2fs_write_end_io
- fscrypt_free_bounce_page
: freed bounced page which belongs to page #2
- inc_page_count( , WB_DATA_TYPE(data_folio), false)
: data_folio points to fio->encrypted_page
the bounced page can be freed before
accessing it in f2fs_is_cp_guarantee()
It can reproduce w/ below testcase:
Run below script in shell #1:
for ((i=1;i>0;i++)) do xfs_io -f /mnt/f2fs/enc/file \
-c "pwrite 0 32k" -c "fdatasync"
Run below script in shell #2:
for ((i=1;i>0;i++)) do xfs_io -f /mnt/f2fs/enc/file \
-c "pwrite 0 32k" -c "fdatasync"
So, in f2fs_merge_page_bio(), let's avoid using fio->encrypted_page after
commit page into internal ipu cache.
CVE-2025-40051HIGH(7.8)
EPSS 0.2%
In the Linux kernel, the following vulnerability has been resolved:
vhost: vringh: Modify the return value check
The return value of copy_from_iter and copy_to_iter can't be negative,
check whether the copied lengths are equal.
CVE-2025-40067HIGH(7.8)
EPSS 0.2%
In the Linux kernel, the following vulnerability has been resolved:
fs/ntfs3: reject index allocation if $BITMAP is empty but blocks exist
Index allocation requires at least one bit in the $BITMAP attribute to
track usage of index entries. If the bitmap is empty while index blocks
are already present, this reflects on-disk corruption.
syzbot triggered this condition using a malformed NTFS image. During a
rename() operation involving a long filename (which spans multiple
index entries), the empty bitmap allowed the name to be added without
valid tracking. Subsequent deletion of the original entry failed with
-ENOENT, due to unexpected index state.
Reject such cases by verifying that the bitmap is not empty when index
blocks exist.