| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| Second, the audio buffer backing a mapping could be freed when the device was closed even though the mapping remained valid. The freed memory could then be reused elsewhere while still accessible through the stale mapping.
The /dev/dsp device nodes are world-accessible by default. On a system with an audio device, either issue allows an unprivileged local user to read and write kernel memory, which can be used to escalate privileges, potentially gaining full control of the affected system. At a minimum, an attacker can crash the kernel, resulting in a Denial of Service (DoS). |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: timer: Fix UAF at snd_timer_user_params()
At releasing a timer object, e.g. when a userspace timer
(CONFIG_SND_UTIMER) gets closed and snd_timer_free() is called, it
tries to detach the timer instances and release the resources.
However, it's still possible that other in-flight tasks are holding
the timer instance where the to-be-deleted timer object is associated,
and this may lead to racy accesses.
Fortunately, most of ioctls dealing with the timer instance list
already have the protection with register_mutex, and this also avoids
such races. But, SNDRV_TIMER_IOCTL_PARAMS isn't protected, hence the
concurrent ioctl may lead to use-after-free.
This patch just adds the guard with register_mutex to protect
snd_timer_user_params() for covering the code path as a quick
workaround. It's no hot-path but rather a rarely issued ioctl, so the
performance penalty doesn't matter. |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: ISO: Fix a use-after-free of the hci_conn pointer
In iso_sock_rebind_bc(), the bis pointer is cached, then the socket lock is
dropped:
bis = iso_pi(sk)->conn->hcon;
/* Release the socket before lookups since that requires hci_dev_lock
* which shall not be acquired while holding sock_lock for proper
* ordering.
*/
release_sock(sk);
hci_dev_lock(bis->hdev);
During the unlocked window, could a concurrent close() destroy the connection
and free the bis structure, causing hci_dev_lock(bis->hdev) to access memory
after it is freed, fix this by using the hdev reference which was safely
acquired via iso_conn_get_hdev(). |
| In the Linux kernel, the following vulnerability has been resolved:
iommu/vt-d: Avoid NULL pointer dereference or refcount corruption
Commit 60f030f7418d ("iommu/vt-d: Avoid use of NULL after WARN_ON_ONCE")
fixed a NULL pointer dereference in an unlikely situation partly.
If dev_pasid is not found in the dev_pasids list, it remains NULL.
However, the teardown operations are executed unconditionally, this lead
to a NULL pointer dereference or refcount corruption.
If the domain was never attached to this IOMMU, info will be NULL, which
would cause an immediate dereference when checking --info->refcnt.
Even if info is not NULL, decrementing the refcount without having removed
a valid PASID might unbalance the count. This could lead to premature
dropping of the refcount to 0, potentially causing a use-after-free for the
remaining active devices sharing the domain.
Fix it by returning early if dev_pasid is NULL, before executing the
teardown operations.
Issue found by AI review and suggested by Kevin Tian.
https://sashiko.dev/#/patchset/20260421031347.1408890-1-zhenzhong.duan%40intel.com |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix use-after-free from async crypto on Qualcomm crypto engine
ksmbd_crypt_message() sets a NULL completion callback on AEAD requests
and does not handle the -EINPROGRESS return code from async hardware
crypto engines like the Qualcomm Crypto Engine (QCE). When QCE returns
-EINPROGRESS, ksmbd treats it as an error and immediately frees the
request while the hardware DMA operation is still in flight. The DMA
completion callback then dereferences freed memory, causing a NULL
pointer crash:
pc : qce_skcipher_done+0x24/0x174
lr : vchan_complete+0x230/0x27c
...
el1h_64_irq+0x68/0x6c
ksmbd_free_work_struct+0x20/0x118 [ksmbd]
ksmbd_exit_file_cache+0x694/0xa4c [ksmbd]
Use the standard crypto_wait_req() pattern with crypto_req_done() as
the completion callback, matching the approach used by the SMB client
in fs/smb/client/smb2ops.c. This properly handles both synchronous
engines (immediate return) and async engines (-EINPROGRESS followed
by callback notification). |
| In the Linux kernel, the following vulnerability has been resolved:
misc: fastrpc: fix use-after-free of fastrpc_user in workqueue context
There is a race between fastrpc_device_release() and the workqueue
that processes DSP responses. When the user closes the file descriptor,
fastrpc_device_release() frees the fastrpc_user structure. Concurrently,
an in-flight DSP invocation can complete and fastrpc_rpmsg_callback()
schedules context cleanup via schedule_work(&ctx->put_work). If the
workqueue runs fastrpc_context_free() in parallel with or after
fastrpc_device_release() has freed the user structure, it dereferences
the freed fastrpc_user. Depending on the state of the context at the
time of the race, any one of the following accesses can be hit:
1. fastrpc_buf_free() calls fastrpc_ipa_to_dma_addr(buf->fl->cctx, ...)
to strip the SID bits from the stored IOVA before passing the
physical address to dma_free_coherent().
2. fastrpc_free_map() reads map->fl->cctx->vmperms[0].vmid to
reconstruct the source permission bitmask needed for the
qcom_scm_assign_mem() call that returns memory from the DSP VM
back to HLOS.
3. fastrpc_free_map() acquires map->fl->lock to safely remove the
map node from the fl->maps list.
The resulting use-after-free manifests as:
pc : fastrpc_buf_free+0x38/0x80 [fastrpc]
lr : fastrpc_context_free+0xa8/0x1b0 [fastrpc]
fastrpc_context_free+0xa8/0x1b0 [fastrpc]
fastrpc_context_put_wq+0x78/0xa0 [fastrpc]
process_one_work+0x180/0x450
worker_thread+0x26c/0x388
Add kref-based reference counting to fastrpc_user. Have each invoke
context take a reference on the user at allocation time and release it
when the context is freed. Release the initial reference in
fastrpc_device_release() at file close. Move the teardown of the user
structure — freeing pending contexts, maps, mmaps, and the channel
context reference — into the kref release callback fastrpc_user_free(),
so that it runs only when the last reference is dropped, regardless of
whether that happens at device close or after the final in-flight
context completes. |
| In the Linux kernel, the following vulnerability has been resolved:
greybus: raw: fix use-after-free on cdev close
This addresses a use-after-free bug when a raw bundle is disconnected
but its chardev is still opened by an application. When the application
releases the cdev, it causes the following panic when init on free is
enabled (CONFIG_INIT_ON_FREE_DEFAULT_ON=y):
refcount_t: underflow; use-after-free.
WARNING: CPU: 0 PID: 139 at lib/refcount.c:28 refcount_warn_saturate+0xd0/0x130
...
Call Trace:
<TASK>
cdev_put+0x18/0x30
__fput+0x255/0x2a0
__x64_sys_close+0x3d/0x80
do_syscall_64+0xa4/0x290
entry_SYSCALL_64_after_hwframe+0x77/0x7f
The cdev is contained in the "gb_raw" structure, which is freed in the
disconnect operation. When the cdev is released at a later time,
cdev_put gets an address that points to freed memory.
To fix this use-after-free, convert the struct device from a pointer to
being embedded, that makes the lifetime of the cdev and of this device
the same. Then, use cdev_device_add, which guarantees that the device
won't be released until all references to the cdev have been released.
Finally, delegate the freeing of the structure to the device release
function, instead of freeing immediately in the disconnect callback. |
| In the Linux kernel, the following vulnerability has been resolved:
tee: optee: prevent use-after-free when the client exits before the supplicant
Commit 70b0d6b0a199 ("tee: optee: Fix supplicant wait loop") made the
client wait as killable so it can be interrupted during shutdown or
after a supplicant crash. This changes the original lifetime expectations:
the client task can now terminate while the supplicant is still processing
its request.
If the client exits first it removes the request from its queue and
kfree()s it, while the request ID remains in supp->idr. A subsequent
lookup on the supplicant path then dereferences freed memory, leading to
a use-after-free.
Serialise access to the request with supp->mutex:
* Hold supp->mutex in optee_supp_recv() and optee_supp_send() while
looking up and touching the request.
* Let optee_supp_thrd_req() notice that the client has terminated and
signal optee_supp_send() accordingly.
With these changes the request cannot be freed while the supplicant still
has a reference, eliminating the race. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: anycast: insert aca into global hash under idev->lock
syzbot reported a splat [1]: a slab-use-after-free in
ipv6_chk_acast_addr(), which walks the global inet6_acaddr_lst[] hash
under RCU and dereferences a struct ifacaddr6 that has already been
freed while still linked in the hash, so a later reader walks into a
dangling node.
In __ipv6_dev_ac_inc() the aca is allocated with refcount 1, then
aca_get() bumps it to 2 to keep it alive across the unlocked region.
It is published to idev->ac_list under idev->lock, but
ipv6_add_acaddr_hash() runs after write_unlock_bh(). A concurrent
teardown (ipv6_ac_destroy_dev() from addrconf_ifdown(), under RTNL)
can slip into that window:
CPU0 __ipv6_dev_ac_inc CPU1 ipv6_ac_destroy_dev (RTNL)
------------------------------ ------------------------------------
aca_alloc() refcnt 1
aca_get() refcnt 2
write_lock_bh(idev->lock)
add aca to ac_list
write_unlock_bh(idev->lock)
write_lock_bh(idev->lock)
pull aca off ac_list
write_unlock_bh(idev->lock)
ipv6_del_acaddr_hash(aca)
hlist_del_init_rcu() is a no-op,
aca is not in the hash yet
aca_put() refcnt 2->1
ipv6_add_acaddr_hash(aca)
aca now inserted into the hash
aca_put() refcnt 1->0
call_rcu(aca_free_rcu) -> kfree(aca)
The hash removal becomes a no-op because the insertion has not
happened yet, so once CPU0 inserts and drops the last reference, the
aca is freed while still linked in inet6_acaddr_lst[], and readers
dereference freed memory after the slab slot is reused.
This window opened once RTNL stopped serializing the join path against
device teardown. Move ipv6_add_acaddr_hash() inside the idev->lock
section so the ac_list and hash insertions are atomic with respect to
teardown: a racing remover now either misses the aca entirely or finds
it in both lists.
acaddr_hash_lock is now nested under idev->lock, which is acquired in
softirq context, so switch all acaddr_hash_lock sites to spin_lock_bh()
to avoid the irq lock inversion reported in [2].
[1] https://syzkaller.appspot.com/bug?extid=a01df04303c131efbf3a
[2] https://lore.kernel.org/netdev/6a194ef7.ba3b1513.1890b4.0000.GAE@google.com/ |
| In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: RFCOMM: hold listener socket in rfcomm_connect_ind()
rfcomm_get_sock_by_channel() scans rfcomm_sk_list under the list lock,
but returns the selected listener after dropping that lock without
taking a reference. rfcomm_connect_ind() then locks the listener,
queues a child socket on it, and may notify it after unlocking it.
The buggy scenario involves two paths, with each column showing the
order within that path:
rfcomm_connect_ind(): listener close:
1. Find parent in 1. close() enters
rfcomm_get_sock_by_channel() rfcomm_sock_release().
2. Drop rfcomm_sk_list.lock 2. rfcomm_sock_shutdown()
without pinning parent. closes the listener.
3. Call lock_sock(parent) and 3. rfcomm_sock_kill()
bt_accept_enqueue(parent, unlinks and puts parent.
sk, true).
4. Read parent flags and may 4. parent can be freed.
call sk_state_change().
If close wins the race, parent can be freed before
rfcomm_connect_ind() reaches lock_sock(), bt_accept_enqueue(), or the
deferred-setup callback.
Take a reference on the listener before leaving rfcomm_sk_list.lock.
After lock_sock() succeeds, recheck that it is still in BT_LISTEN
before queueing a child, cache the deferred-setup bit while the parent
is locked, and drop the reference after the last parent use.
KASAN reported a slab-use-after-free in lock_sock_nested() from
rfcomm_connect_ind(), with the freeing stack going through
rfcomm_sock_kill() and rfcomm_sock_release(). |
| In the Linux kernel, the following vulnerability has been resolved:
net: airoha: Fix use-after-free in metadata dst teardown
airoha_metadata_dst_free() runs metadata_dst_free() which frees the
metadata_dst with kfree() immediately, bypassing the RCU grace period.
In the RX path, skb_dst_set_noref() sets a non-refcounted pointer from
the skb to the metadata_dst. This function requires RCU read-side
protection and the dst must remain valid until all RCU readers complete.
Since metadata_dst_free() calls kfree() directly, an use-after-free can
occur if any skb still holds a noref pointer to the dst when the driver
tears it down.
Replace metadata_dst_free() with dst_release() which properly goes
through the refcount path: when the refcount drops to zero, it schedules
the actual free via call_rcu_hurry(), ensuring all RCU readers have
completed before the memory is freed. |
| In the Linux kernel, the following vulnerability has been resolved:
net: ethernet: mtk_eth_soc: Fix use-after-free in metadata dst teardown
mtk_free_dev() calls metadata_dst_free() which frees the metadata_dst
with kfree() immediately, bypassing the RCU grace period.
In the RX path, skb_dst_set_noref() sets a non-refcounted pointer from
the skb to the metadata_dst. This function requires RCU read-side
protection and the dst must remain valid until all RCU readers complete.
Since metadata_dst_free() calls kfree() directly, a use-after-free can
occur if any skb still holds a noref pointer to the dst when the driver
tears it down.
Replace metadata_dst_free() with dst_release() which properly goes
through the refcount path: when the refcount drops to zero, it schedules
the actual free via call_rcu_hurry(), ensuring all RCU readers have
completed before the memory is freed. |
| In the Linux kernel, the following vulnerability has been resolved:
xfrm: iptfs: fix use-after-free on first_skb in __input_process_payload
__input_process_payload() stores first_skb into xtfs->ra_newskb under
drop_lock when starting partial reassembly, then unlocks and breaks out
of the processing loop. The post-loop check reads xtfs->ra_newskb
without the lock to decide whether first_skb is still owned:
if (first_skb && first_iplen && !defer && first_skb != xtfs->ra_newskb)
Between spin_unlock and this read, a concurrent CPU running
iptfs_reassem_cont() (or the drop_timer hrtimer) can complete
reassembly, NULL xtfs->ra_newskb, and free the skb. The check then
evaluates first_skb != NULL as true, and pskb_trim/ip_summed/consume_skb
operate on the freed skb — a use-after-free in skbuff_head_cache.
Replace the unlocked read with a local bool that records whether
first_skb was handed to the reassembly state in the current call. The
flag is set after the existing spin_unlock, before the break, using the
pointer equality that is stable at that point (first_skb == skb iff
first_skb was stored in ra_newskb). |
| 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. |
| 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. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: timer: Forcibly close timer instances at closing
When snd_timer object is freed via snd_timer_free() and still pending
snd_timer_instance objects are assigned to the timer object, it tries
to unlink all instances and just set NULL to each ti->timer, then
releases the resources immediately. The problem is, however, when
there are slave timer instances that are associated with a master
instance linked to this timer: namely, those slave instances still
point to the freed timer object although the master instance is
unlinked, which may lead to user-after-free. The bug can be easily
triggered particularly when a new userspace-driven timers
(CONFIG_SND_UTIMER) is involved, since it can create and delete the
timer object via a simple file open/close, while the other
applications may keep accessing to that timer.
This patch is an attempt to paper over the problem above: now instead
of just unlinking, call snd_timer_close[_locked]() forcibly for each
pending timer instance, so that all assigned slave timer instances are
properly detached, too. Since snd_timer_close() might be called later
by the driver that created that instance, the check of
SNDRV_TIMER_IFLG_DEAD is added at the beginning, too. |
| In the Linux kernel, the following vulnerability has been resolved:
misc: fastrpc: fix use-after-free race in fastrpc_map_create
fastrpc_map_lookup returns a raw pointer after releasing fl->lock. The
caller fastrpc_map_create then calls fastrpc_map_get (kref_get_unless_zero)
on this unprotected pointer. A concurrent MEM_UNMAP can free the map
between the lock release and the kref operation, resulting in a
use-after-free on the freed slab object.
Restore the take_ref parameter to fastrpc_map_lookup so the reference
is acquired atomically under fl->lock before the pointer is exposed to
the caller. |
| In the Linux kernel, the following vulnerability has been resolved:
bpf: fix mm lifecycle in open-coded task_vma iterator
The open-coded task_vma iterator reads task->mm locklessly and acquires
mmap_read_trylock() but never calls mmget(). If the task exits
concurrently, the mm_struct can be freed as it is not
SLAB_TYPESAFE_BY_RCU, resulting in a use-after-free.
Safely read task->mm with a trylock on alloc_lock and acquire an mm
reference. Drop the reference via bpf_iter_mmput_async() in _destroy()
and error paths. bpf_iter_mmput_async() is a local wrapper around
mmput_async() with a fallback to mmput() on !CONFIG_MMU.
Reject irqs-disabled contexts (including NMI) up front. Operations used
by _next() and _destroy() (mmap_read_unlock, bpf_iter_mmput_async)
take spinlocks with IRQs disabled (pool->lock, pi_lock). Running from
NMI or from a tracepoint that fires with those locks held could
deadlock.
A trylock on alloc_lock is used instead of the blocking task_lock()
(get_task_mm) to avoid a deadlock when a softirq BPF program iterates
a task that already holds its alloc_lock on the same CPU. |
| In the Linux kernel, the following vulnerability has been resolved:
crypto: hisilicon/sec2 - prevent req used-after-free for sec
During packet transmission, if the system is under heavy load,
the hardware might complete processing the packet and free the
request memory (req) before the transmission function finishes.
If the software subsequently accesses this req, a use-after-free
error will occur. The qp_ctx memory exists throughout the packet
sending process, so replace the req with the qp_ctx. |
| In the Linux kernel, the following vulnerability has been resolved:
ocfs2: validate bg_bits during freefrag scan
[BUG]
A crafted filesystem can trigger an out-of-bounds bitmap walk when
OCFS2_IOC_INFO is issued with OCFS2_INFO_FL_NON_COHERENT.
BUG: KASAN: use-after-free in instrument_atomic_read include/linux/instrumented.h:68 [inline]
BUG: KASAN: use-after-free in _test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
BUG: KASAN: use-after-free in test_bit_le include/asm-generic/bitops/le.h:21 [inline]
BUG: KASAN: use-after-free in ocfs2_info_freefrag_scan_chain fs/ocfs2/ioctl.c:495 [inline]
BUG: KASAN: use-after-free in ocfs2_info_freefrag_scan_bitmap fs/ocfs2/ioctl.c:588 [inline]
BUG: KASAN: use-after-free in ocfs2_info_handle_freefrag fs/ocfs2/ioctl.c:662 [inline]
BUG: KASAN: use-after-free in ocfs2_info_handle_request+0x1c66/0x3370 fs/ocfs2/ioctl.c:754
Read of size 8 at addr ffff888031bce000 by task syz.0.636/1435
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0xbe/0x130 lib/dump_stack.c:120
print_address_description mm/kasan/report.c:378 [inline]
print_report+0xd1/0x650 mm/kasan/report.c:482
kasan_report+0xfb/0x140 mm/kasan/report.c:595
check_region_inline mm/kasan/generic.c:186 [inline]
kasan_check_range+0x11c/0x200 mm/kasan/generic.c:200
__kasan_check_read+0x11/0x20 mm/kasan/shadow.c:31
instrument_atomic_read include/linux/instrumented.h:68 [inline]
_test_bit include/asm-generic/bitops/instrumented-non-atomic.h:141 [inline]
test_bit_le include/asm-generic/bitops/le.h:21 [inline]
ocfs2_info_freefrag_scan_chain fs/ocfs2/ioctl.c:495 [inline]
ocfs2_info_freefrag_scan_bitmap fs/ocfs2/ioctl.c:588 [inline]
ocfs2_info_handle_freefrag fs/ocfs2/ioctl.c:662 [inline]
ocfs2_info_handle_request+0x1c66/0x3370 fs/ocfs2/ioctl.c:754
ocfs2_info_handle+0x18d/0x2a0 fs/ocfs2/ioctl.c:828
ocfs2_ioctl+0x632/0x6e0 fs/ocfs2/ioctl.c:913
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:597 [inline]
__se_sys_ioctl fs/ioctl.c:583 [inline]
__x64_sys_ioctl+0x197/0x1e0 fs/ioctl.c:583
...
[CAUSE]
ocfs2_info_freefrag_scan_chain() uses on-disk bg_bits directly as the
bitmap scan limit. The coherent path reads group descriptors through
ocfs2_read_group_descriptor(), which validates the descriptor before
use. The non-coherent path uses ocfs2_read_blocks_sync() instead and
skips that validation, so an impossible bg_bits value can drive the
bitmap walk past the end of the block.
[FIX]
Compute the bitmap capacity from the filesystem format with
ocfs2_group_bitmap_size(), report descriptors whose bg_bits exceeds
that limit, and clamp the scan to the computed capacity. This keeps the
freefrag report going while avoiding reads beyond the buffer. |
