Linux: >> Linux Kernel >> 6.6.104 Security Vulnerabilities
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:
xfs: fail recovery on a committed log item with no regions
If the first op of a transaction is a bare transaction header
(len == sizeof(struct xfs_trans_header)), xlog_recover_add_to_trans()
adds an item but no region, leaving it on r_itemq with ri_cnt == 0 and
ri_buf == NULL.
The header can be split across op records, so later ops may still add
regions; the item is only invalid if the transaction commits with none.
The runtime commit path never emits such a transaction, so this only
happens on a crafted log. It came from an AI-assisted code audit of the
recovery parser.
xlog_recover_reorder_trans() calls ITEM_TYPE() on the item, which reads
*(unsigned short *)item->ri_buf[0].iov_base and faults on the NULL
ri_buf. Reject it there, before the commit handlers that also read
ri_buf[0].
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:xlog_recover_reorder_trans (fs/xfs/xfs_log_recover.c:1836)
xlog_recover_commit_trans (fs/xfs/xfs_log_recover.c:2043)
xlog_recover_process_data (fs/xfs/xfs_log_recover.c:2501)
xlog_do_recovery_pass (fs/xfs/xfs_log_recover.c:3244)
xlog_recover (fs/xfs/xfs_log_recover.c:3493)
xfs_log_mount (fs/xfs/xfs_log.c:618)
xfs_mountfs (fs/xfs/xfs_mount.c:1034)
xfs_fs_fill_super (fs/xfs/xfs_super.c:1938)
vfs_get_tree (fs/super.c:1695)
path_mount (fs/namespace.c:4161)
__x64_sys_mount (fs/namespace.c:4367)
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-20
In the Linux kernel, the following vulnerability has been resolved:
net: qualcomm: rmnet: fix endpoint use-after-free in rmnet_dellink()
rmnet_dellink() removes the endpoint from the hash table with
hlist_del_init_rcu() and then immediately frees it with kfree(). However,
RCU readers on the receive path (rmnet_rx_handler ->
__rmnet_map_ingress_handler) may still hold a reference to the endpoint and
dereference ep->egress_dev after the memory has been freed. The endpoint is
a kmalloc-32 object, and the stale read at offset 8 corresponds to the
egress_dev pointer.
BUG: unable to handle page fault for address: ffffffffde942eef
Oops: 0002 [#1] SMP NOPTI
CPU: 1 UID: 0 PID: 137 Comm: poc_write Not tainted 7.0.0+ #4 PREEMPTLAZY
RIP: 0010:rmnet_vnd_rx_fixup (rmnet_vnd.c:27)
Call Trace:
<TASK>
__rmnet_map_ingress_handler (rmnet_handlers.c:48 rmnet_handlers.c:101)
rmnet_rx_handler (rmnet_handlers.c:129 rmnet_handlers.c:235)
__netif_receive_skb_core.constprop.0 (net/core/dev.c:6096)
__netif_receive_skb_one_core (net/core/dev.c:6208)
netif_receive_skb (net/core/dev.c:6467)
tun_get_user (drivers/net/tun.c:1955)
tun_chr_write_iter (drivers/net/tun.c:2003)
vfs_write (fs/read_write.c:688)
ksys_write (fs/read_write.c:740)
</TASK>
Add an rcu_head field to struct rmnet_endpoint and replace kfree() with
kfree_rcu() so the endpoint memory remains valid through the RCU grace
period. Also remove the rmnet_vnd_dellink() call and inline only the
nr_rmnet_devs decrement, since rmnet_vnd_dellink() would set
ep->egress_dev to NULL during the grace period, creating a data race
with lockless readers.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-20
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ipset: fix race between dump and ip_set_list resize
The release path of ip_set_dump_do() and ip_set_dump_done() read
inst->ip_set_list via ip_set_ref_netlink(), a plain rcu_dereference_raw()
of the array pointer. These run from netlink_recvmsg() without the nfnl
mutex and without an RCU read-side critical section.
A concurrent ip_set_create() can grow the array: it publishes the new
array, calls synchronize_net() and then kvfree()s the old one. Since the
dump paths read the array outside any RCU reader, synchronize_net() does
not wait for them and the old array can be freed while they still index
into it, causing a use-after-free.
The dumped set itself stays pinned via set->ref_netlink, so only the
array load needs protecting. Take rcu_read_lock() around it, matching
ip_set_get_byname() and __ip_set_put_byindex().
BUG: KASAN: slab-use-after-free in ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697)
Read of size 8 at addr ffff88800b5c4018 by task exploit/150
Call Trace:
...
kasan_report (mm/kasan/report.c:595)
ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1697)
netlink_dump (net/netlink/af_netlink.c:2325)
netlink_recvmsg (net/netlink/af_netlink.c:1976)
sock_recvmsg (net/socket.c:1159)
__sys_recvfrom (net/socket.c:2315)
...
Oops: general protection fault, probably for non-canonical address ... KASAN NOPTI
KASAN: maybe wild-memory-access in range [0x02d6...d0-0x02d6...d7]
RIP: 0010:ip_set_dump_do (net/netfilter/ipset/ip_set_core.c:1698)
Kernel panic - not syncing: Fatal exception
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-20
In the Linux kernel, the following vulnerability has been resolved:
efi: Allocate runtime workqueue before ACPI init
Since commit
5894cf571e14 ("acpi/prmt: Use EFI runtime sandbox to invoke PRM handlers")
ACPI PRM calls are delegated to a workqueue which runs in a kernel
thread, making it easier to detect and mitigate faulting memory accesses
performed by the firmware.
Rafael reports that such PRM accesses may occur before efisubsys_init()
executes, which is where the workqueue is allocated, leading to NULL
pointer dereferences. Since acpi_init() [which triggers the early PRM
accesses] executes as a subsys_initcall() as well, and has its own
dependencies that may be sensitive to initcall ordering, deferring
acpi_init() is not an option.
So instead, split off the workqueue allocation into its own postcore
initcall, as this is the only missing piece to allow EFI runtime calls
to be made. This ensures that EFI runtime call (including PRM calls) are
accessible to all code running at subsys_initcall() level.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/sysfs-schemes: call missing mem_cgroup_iter_break()
damon_sysfs_memcg_path_to_id() breaks mem_cgroup_iter() loop without
calling mem_cgroup_iter_break(). This leaks the cgroup reference. Fix
the issue by calling mem_cgroup_iter_break() before the break.
The issue was discovered [1] by Sashiko.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: bnep: Fix UAF read of dev->name
bnep_add_connection() needs to keep holding the bnep_session_sem while
reading dev->name (just like bnep_get_connlist() does); otherwise the
bnep_session() thread can concurrently free the net_device, which can for
example be triggered by a concurrent bnep_del_connection().
(This UAF is fairly uninteresting from a security perspective;
calling bnep_add_connection() requires passing a capable(CAP_NET_ADMIN)
check. It also requires completely tearing down a netdev during a fairly
tight race window.)
CVSS Score
8.8
EPSS Score
0.002
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
net: wwan: iosm: fix potential memory leaks in ipc_imem_init()
The memory allocated in ipc_protocol_init() is not freed on the error
paths that follow in ipc_imem_init(). Fix that by calling the
corresponding release function ipc_protocol_deinit() in the error path.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
ipv6: ioam: add NULL check for idev in ipv6_hop_ioam()
Reported by Sashiko:
The function ipv6_hop_ioam() accesses
__in6_dev_get(skb->dev)->cnf.ioam6_enabled without validating the returned
idev pointer. Because addrconf_ifdown() can concurrently clear dev->ip6_ptr
via RCU, __in6_dev_get() can return NULL during interface teardown, which
could cause a NULL pointer dereference when processing an IOAM Hop-by-Hop
option.
Let's add a check and use SKB_DROP_REASON_IPV6DISABLED accordingly.
CVSS Score
7.5
EPSS Score
0.005
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
af_unix: Fix UAF read of tail->len in unix_stream_data_wait()
unix_stream_data_wait() does skb_peek_tail(&sk->sk_receive_queue) without
holding any lock that prevents SKBs on that queue from being dequeued and
freed.
This has been the case since commit 79f632c71bea ("unix/stream: fix
peeking with an offset larger than data in queue").
The first consequence of this is that the pointer comparison
`tail != last` can be false even if `last` semantically refers to an
already-freed SKB while `tail` is a new SKB allocated at the same address;
which can cause unix_stream_data_wait() to wrongly keep blocking after new
data has arrived, but only in a weird scenario where a peeking recv() and
a normal recv() on the same socket are racing, which is probably not a
real problem.
But since commit 2b514574f7e8 ("net: af_unix: implement splice for stream
af_unix sockets"), `tail` is actually dereferenced, which can cause UAF in
the following race scenario (where test_setup() runs single-threaded,
and afterwards, test_thread1() and test_thread2() run concurrently in
two threads:
```
static int socks[2];
void test_setup(void) {
socketpair(AF_UNIX, SOCK_STREAM, 0, socks);
send(socks[1], "A", 1, 0);
int peekoff = 1;
setsockopt(socks[0], SOL_SOCKET, SO_PEEK_OFF, &peekoff, sizeof(peekoff));
}
void test_thread1(void) {
char dummy;
recv(socks[0], &dummy, 1, MSG_PEEK);
}
void test_thread2(void) {
char dummy;
recv(socks[0], &dummy, 1, 0);
shutdown(socks[1], SHUT_WR);
}
```
when racing like this:
```
thread1 thread2
unix_stream_read_generic
mutex_lock(&u->iolock)
skb_peek(&sk->sk_receive_queue)
skb_peek_next(skb, &sk->sk_receive_queue)
mutex_unlock(&u->iolock)
unix_stream_read_generic
unix_state_lock(sk)
skb_peek(&sk->sk_receive_queue)
unix_state_unlock(sk)
unix_stream_data_wait
unix_state_lock(sk)
tail = skb_peek_tail(&sk->sk_receive_queue)
spin_lock(&sk->sk_receive_queue.lock)
__skb_unlink(skb, &sk->sk_receive_queue)
spin_unlock(&sk->sk_receive_queue.lock)
consume_skb(skb) [frees the SKB]
`tail != last`: false
`tail`: true
`tail->len != last_len` ***UAF***
```
Fix the UAF by removing the read of tail->len; checking tail->len would
only make sense if SKBs in the receive queue of a UNIX socket could grow,
which can no longer happen.
Kuniyuki explained:
> When commit 869e7c62486e ("net: af_unix: implement stream sendpage
> support") added sendpage() support, data could be appended to the last
> skb in the receiver's queue.
>
> That's why we needed to check if the length of the last skb was changed
> while waiting for new data in unix_stream_data_wait().
>
> However, commit a0dbf5f818f9 ("af_unix: Support MSG_SPLICE_PAGES") and
> commit 57d44a354a43 ("unix: Convert unix_stream_sendpage() to use
> MSG_SPLICE_PAGES") refactored sendmsg(), and now data is always added
> to a new skb.
That means this fix is not suitable for kernels before 6.5.
CVSS Score
8.8
EPSS Score
0.001
Published
2026-07-19