Linux: >> Linux Kernel >> 6.11.8 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
mm/memory-failure: fix hugetlb_lock AA deadlock in get_huge_page_for_hwpoison
Two concurrent madvise(MADV_HWPOISON) calls on the same hugetlb page can
trigger a recursive spinlock self-deadlock (AA deadlock) on hugetlb_lock
when racing with a concurrent unmap:
thread#0 thread#1
-------- --------
madvise(folio, MADV_HWPOISON)
-> poisons the folio successfully
madvise(folio, MADV_HWPOISON) unmap(folio)
try_memory_failure_hugetlb
get_huge_page_for_hwpoison
spin_lock_irq(&hugetlb_lock) <- held
__get_huge_page_for_hwpoison
hugetlb_update_hwpoison()
-> MF_HUGETLB_FOLIO_PRE_POISONED
goto out:
folio_put()
refcount: 1 -> 0
free_huge_folio()
spin_lock_irqsave(&hugetlb_lock)
-> AA DEADLOCK!
The out: path in __get_huge_page_for_hwpoison() calls folio_put() to drop
the GUP reference while the hugetlb_lock is still held by the hugetlb.c
wrapper get_huge_page_for_hwpoison(). If concurrent unmap has released
the page table mapping reference, folio_put() drops the folio refcount to
zero, triggering free_huge_folio() which attempts to re-acquire the
non-recursive hugetlb_lock.
Fix this by moving hugetlb_lock acquisition from the hugetlb.c wrapper
into get_huge_page_for_hwpoison(). Place spin_unlock_irq() before the
folio_put() at the out: label so the folio is always released outside the
lock.
[akpm@linux-foundation.org: fix race, rename label per Miaohe]
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: reject BR/EDR signaling packets over MTUsig
net/bluetooth/l2cap_core.c:l2cap_sig_channel() accepts BR/EDR
signaling packets up to the channel MTU and dispatches each command
without enforcing the signaling MTU (MTUsig). A Bluetooth BR/EDR peer
within radio range can send a fixed-channel CID 0x0001 packet that is
larger than MTUsig and contains many L2CAP_ECHO_REQ commands before
pairing. In a real-radio stock-kernel run, one 681-byte signaling
packet containing 168 zero-length ECHO_REQ commands made the target
transmit 168 ECHO_RSP frames over about 220 ms.
Impact: a Bluetooth BR/EDR peer within radio range, before pairing, can
force 168 ECHO_RSP frames from one 681-byte fixed-channel signaling
packet containing packed ECHO_REQ commands.
Define Linux's BR/EDR signaling MTU as the spec minimum of 48 bytes and
reject any larger signaling packet with one L2CAP_COMMAND_REJECT_RSP
carrying L2CAP_REJ_MTU_EXCEEDED before any command is dispatched.
The Bluetooth Core spec wording for MTUExceeded says the reject
identifier shall match the first request command in the packet, and
that packets containing only responses shall be silently discarded.
Linux intentionally deviates from that prescription: silently
discarding desynchronizes the peer because the remote stack never
learns its responses were dropped, and locating the first request
command requires walking command headers past MTUsig, i.e. processing
bytes from a packet we have already decided is too large to process.
We therefore always emit one reject and use the identifier from the
first command header, a single fixed-offset byte read.
The unrestricted BR/EDR signaling parser and ECHO_REQ response path both
trace to the initial git import; no later introducing commit is
available for a Fixes tag.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
tee: shm: fix shm leak in register_shm_helper()
register_shm_helper() allocates shm before calling
iov_iter_npages(). If iov_iter_npages() returns 0, the function
jumps to err_ctx_put and leaks shm.
This can be triggered by TEE_IOC_SHM_REGISTER with
struct tee_ioctl_shm_register_data where length is 0.
Jump to err_free_shm instead.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_tunnel: fix use-after-free on object destroy
nft_tunnel_obj_destroy() calls metadata_dst_free() which directly
kfree()s the metadata_dst, ignoring the dst_entry refcount. Packets
that took a reference via dst_hold() in nft_tunnel_obj_eval() and
are still queued (e.g. in a netem qdisc) are left with a dangling
pointer. When these packets are eventually dequeued, dst_release()
operates on freed memory.
Replace metadata_dst_free() with dst_release() so the metadata_dst
is freed only after all references are dropped. The dst subsystem
already handles metadata_dst cleanup in dst_destroy() when
DST_METADATA is set.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
drm/vc4: fix krealloc() memory leak
Don't just overwrite the original pointer passed to krealloc()
with its return value without checking latter:
MEM = krealloc(MEM, SZ, GFP);
If krealloc() returns NULL, that erases the pointer
to the still allocated memory, hence leaks this memory.
Instead, use a temporary variable, check it's not NULL
and only then assign it to the original pointer:
TMP = krealloc(MEM, SZ, GFP);
if (!TMP) return;
MEM = TMP;
While on it, use krealloc_array().
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
USB: serial: io_ti: fix heap overflow in get_manuf_info()
get_manuf_info() reads le16_to_cpu(rom_desc->Size) bytes from the
device I2C EEPROM into a buffer allocated with kmalloc_obj(), which
is sizeof(struct edge_ti_manuf_descriptor) = 10 bytes.
The Size field comes from the device and is only validated (in
check_i2c_image()) to make sure the descriptor fits within
TI_MAX_I2C_SIZE (16384 bytes), not against the destination buffer size.
A malicious USB device can therefore set Size to any value up to 16377,
causing a heap overflow of up to 16367 bytes when plugged into a host
running this driver.
valid_csum() is called after read_rom() and also iterates
buffer[0..Size-1], compounding the out-of-bounds access.
Fix by rejecting descriptors with unexpected length before calling
read_rom().
[ johan: amend commit message; also check for short descriptors ]
CVSS Score
6.8
EPSS Score
0.003
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix use-after-free of a deferred file_lock on double SMB2_CANCEL
A deferred byte-range lock (an SMB2_LOCK that blocks) registers an async work on
conn->async_requests via setup_async_work(), with cancel_fn =
smb2_remove_blocked_lock and cancel_argv[0] pointing at the struct file_lock.
When the request is cancelled, the worker frees the file_lock with
locks_free_lock() and takes the cancelled early-exit, which "goto out"s and never
reaches release_async_work() -- the only site that unlinks the work from
conn->async_requests and clears cancel_fn/cancel_argv. The work therefore stays
matchable on async_requests with a live cancel_fn pointing at the freed file_lock,
until connection teardown finally runs release_async_work().
smb2_cancel() fires cancel_fn unconditionally with no state guard, so a second
SMB2_CANCEL for the same AsyncId, arriving in that window, re-runs
smb2_remove_blocked_lock() on the freed file_lock -- a slab use-after-free:
BUG: KASAN: slab-use-after-free in __locks_delete_block
__locks_delete_block
locks_delete_block
ksmbd_vfs_posix_lock_unblock
smb2_remove_blocked_lock
smb2_cancel <- 2nd SMB2_CANCEL fires cancel_fn
handle_ksmbd_work
Allocated by ...: locks_alloc_lock <- smb2_lock
Freed by ...: locks_free_lock <- smb2_lock (cancelled branch)
... cache file_lock_cache of size 192
Reproduced on mainline with KASAN by an authenticated SMB client.
Skip a work whose state is already KSMBD_WORK_CANCELLED so its cancel callback
cannot be fired a second time.
CVSS Score
8.8
EPSS Score
0.005
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
hv_netvsc: use kmap_local_page in netvsc_copy_to_send_buf
netvsc_copy_to_send_buf() copies page buffer entries into the VMBus
send buffer using phys_to_virt() on the entry PFN. Entries for the
RNDIS header and the skb linear data come from kmalloc'd memory and
are always in the kernel direct map, but entries for skb fragments
reference page cache or user pages, which on 32-bit x86 with
CONFIG_HIGHMEM=y can live above the LOWMEM boundary. For such a page
phys_to_virt() returns an address outside the direct map and the
subsequent memcpy() faults on the transmit softirq path, which is
fatal.
Map the pages with kmap_local_page() instead, handling two properties
of the page buffer entries:
- pb[i].pfn is a Hyper-V PFN at HV_HYP_PAGE_SIZE (4K) granularity,
not a native PFN. Reconstruct the physical address first and derive
the native page from it, so the mapping stays correct where
PAGE_SIZE > HV_HYP_PAGE_SIZE (e.g. arm64 with 64K pages).
- Since commit 41a6328b2c55 ("hv_netvsc: Preserve contiguous PFN
grouping in the page buffer array"), an entry describes a full
physically contiguous fragment and pb[i].len can exceed PAGE_SIZE,
while kmap_local_page() maps a single page. Copy page by page,
splitting at native page boundaries.
The copy path only handles packets smaller than the send section size
(6144 bytes by default); larger packets take the cp_partial path where
only the RNDIS header is copied. So entries here are bounded by the
section size and a copy is split at most once on 4K-page systems. On
!CONFIG_HIGHMEM configs kmap_local_page() folds to page_address() and
no mapping work is added.
CVSS Score
7.5
EPSS Score
0.005
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
accel/ivpu: Fix signed integer truncation in IPC receive
Fix potential buffer overflow where firmware-supplied data_size is cast
to signed int before being used in min_t(). Large unsigned values
(>= 0x80000000) become negative, causing unsigned wraparound and
oversized memcpy operations that can overflow the stack buffer.
Change min_t(int, ...) to min() as both values are unsigned and can be
handled by min() without explicit cast.
CVSS Score
7.8
EPSS Score
0.002
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
accel/ivpu: Add buffer overflow check in MS get_info_ioctl
Add validation that the info size returned from the metric stream info
query is not exceeded when checked against the allocated buffer size.
If the firmware returns a size larger than the buffer, reject the
operation with -EOVERFLOW instead of proceeding with an incorrect
buffer copy.
CVSS Score
7.1
EPSS Score
0.002
Published
2026-06-25