Linux: >> Linux Kernel >> 4.2.3 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: bla: fix report_work leak on backbone_gw purge
batadv_bla_purge_backbone_gw() removes stale backbone gateway entries,
but fails to properly handle their associated report_work:
- If report_work is running, the purge must wait for it to finish before
freeing the backbone_gw, otherwise the worker may access freed memory
(e.g. bat_priv).
- If report_work is pending, the purge must cancel it and release the
reference held for that pending work item.
The previous implementation called hlist_for_each_entry_safe() inside a
spin_lock_bh() section, but cancel_work_sync() may sleep and therefore
cannot be called from within a spinlock-protected region.
Restructure the loop to handle one entry per spinlock critical section:
acquire the lock, find the next entry to purge, remove it from the hash
list, then release the lock before calling cancel_work_sync() and
dropping the hash_entry reference. Repeat until no more entries require
purging.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
wifi: iwlwifi: mld: don't dereference a pointer before NULL checking it
In iwl_mld_remove_link, the link->fw_id is saved at the beginning of the
function so we have it after we freed the link.
But the link pointer can be NULL, and is not checked when the fw_id is
stored.
Fix it by simply freeing the link at the end of the function.
fFixes: 0e66a39f4f0e ("wifi: iwlwifi: fix potential use after free in iwl_mld_remove_link()")
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
i2c: stub: Reject I2C block transfers with invalid length
The I2C_SMBUS_I2C_BLOCK_DATA case in stub_xfer() uses data->block[0]
as the transfer length. The existing check only clamps it to avoid
overrunning the chip->words[256] register array, but does not validate
it against I2C_SMBUS_BLOCK_MAX (32), which is the limit of the union
i2c_smbus_data.block buffer (34 bytes total). The driver is a
development/test tool (CONFIG_I2C_STUB=m, not built by default)
that must be loaded with a chip_addr= parameter.
A local user with access to /dev/i2c-* can issue an I2C_SMBUS ioctl
with I2C_SMBUS_I2C_BLOCK_DATA and data->block[0] > 32, causing
stub_xfer() to read or write past the end of the union
i2c_smbus_data.block buffer:
BUG: KASAN: stack-out-of-bounds in stub_xfer (drivers/i2c/i2c-stub.c:223)
Read of size 1 at addr ffff88800abcfd92 by task exploit/81
Call Trace:
<TASK>
stub_xfer (drivers/i2c/i2c-stub.c:223)
__i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:593)
i2c_smbus_xfer (drivers/i2c/i2c-core-smbus.c:536)
i2cdev_ioctl_smbus (drivers/i2c/i2c-dev.c:391)
i2cdev_ioctl (drivers/i2c/i2c-dev.c:478)
__x64_sys_ioctl (fs/ioctl.c:583)
do_syscall_64 (arch/x86/entry/syscall_64.c:94)
entry_SYSCALL_64_after_hwframe (arch/x86/entry/entry_64.S:130)
</TASK>
The bug exists because i2c-stub implements .smbus_xfer directly,
bypassing the I2C_SMBUS_BLOCK_MAX validation in
i2c_smbus_xfer_emulated(). The I2C_SMBUS_BLOCK_DATA case in the same
function correctly validates against I2C_SMBUS_BLOCK_MAX, but the
I2C_SMBUS_I2C_BLOCK_DATA case does not.
Fix by rejecting transfers with data->block[0] == 0 or
data->block[0] > I2C_SMBUS_BLOCK_MAX with -EINVAL, consistent with
both the I2C_SMBUS_BLOCK_DATA case in the same function and the
I2C_SMBUS_I2C_BLOCK_DATA validation in i2c_smbus_xfer_emulated().
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-20
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:
spi: qup: fix error pointer deref after DMA setup failure
The driver falls back to PIO mode if DMA setup fails during probe.
Make sure to the clear the DMA channel pointers on setup failure to
avoid dereferencing an error pointer (or attempting to release a channel
a second time) on later probe errors or driver unbind.
This issue was flagged by Sashiko when reviewing a devres allocation
conversion patch.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
ALSA: asihpi: Fix potential OOB array access at reading cache
find_control() to retrieve a cached info accesses the array with the
given index blindly, which may lead to an OOB array access.
Add a sanity check for avoiding it.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
net: bcmgenet: keep RBUF EEE/PM disabled
Setting RBUF_EEE_EN | RBUF_PM_EN in RBUF_ENERGY_CTRL breaks the RX
path on GENET hardware once MAC EEE becomes active. RX traffic stops
flowing while the link stays up and the usual descriptor/RX error
counters remain quiet. In that state the MAC still accepts frames
(rbuf_ovflow_cnt keeps climbing) but RBUF no longer forwards them to
DMA, so rx_packets is no longer incremented at the netdev level. On
some boards the corruption ends up as a paging fault in
skb_release_data via bcmgenet_rx_poll on an LPI exit.
Reproduced on Pi 4B (BCM2711 + BCM54213PE) and confirmed by Florian
Fainelli on an internal Broadcom 4908-family board with the same crash
signature. RBUF_PM_EN is not publicly documented.
This shows up more often now that phy_support_eee() enables EEE by
default, but it also affects older kernels as soon as TX LPI is
turned on via ethtool, so it is not specific to recent changes.
Always clear RBUF_EEE_EN | RBUF_PM_EN in bcmgenet_eee_enable_set so
the bits stay off across resets. UMAC and TBUF setup is left alone so
TX-side EEE keeps working.
CVSS Score
9.8
EPSS Score
0.006
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
In the Linux kernel, the following vulnerability has been resolved:
ixgbevf: fix use-after-free in VEPA multicast source pruning
ixgbevf_clean_rx_irq() prunes frames whose source MAC matches the VF's
own address (VEPA multicast workaround) by freeing the skb and
continuing to the next descriptor:
dev_kfree_skb_irq(skb);
continue;
The skb pointer is declared outside the while loop and persists across
iterations. Because the continue skips the "skb = NULL" reset at the
bottom of the loop, the next iteration enters the "else if (skb)" path
and calls ixgbevf_add_rx_frag() on the freed skb, dereferencing
skb_shinfo(skb)->nr_frags - a use-after-free in NAPI softirq context.
The sibling driver iavf already handles this correctly by nulling the
pointer before continuing. Apply the same pattern here.
I do not have ixgbevf hardware; the bug was found by static analysis
(scan_drop_continue_loops.py + semgrep drop_continue_in_loop, multi-tool
corroboration with the highest score in the scan). The UAF was confirmed
under KASAN by loading a test module that reproduces the exact code
pattern (alloc skb, kfree_skb, then read skb_shinfo(skb)->nr_frags):
BUG: KASAN: slab-use-after-free in ixgbevf_uaf_test_init+0x100/0x1000
Read of size 8 at addr 000000006163ae78 by task insmod/30
freed 208-byte region [000000006163adc0, 000000006163ae90)
QEMU emulates igb (82576) but not ixgbe (82599), and the igbvf VF
driver does not include the VEPA source pruning path, so a full
end-to-end reproduction with emulated hardware was not possible.
CVSS Score
9.8
EPSS Score
0.005
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
vsock/vmci: fix UAF when peer resets connection during handshake
vmci_transport_recv_connecting_server() returned err = 0 for a peer
RST in its default switch arm:
err = pkt->type == VMCI_TRANSPORT_PACKET_TYPE_RST ? 0 : -EINVAL;
That made vmci_transport_recv_listen() skip vsock_remove_pending(),
leaving the pending socket on the listener's pending_links with
sk_state = TCP_CLOSE while destroy: still dropped the explicit
reference taken before schedule_delayed_work().
One second later vsock_pending_work() observed is_pending=true and
performed full cleanup: vsock_remove_pending() then the two trailing
sock_put(sk) calls -- the first reached refcount 0 and __sk_freed
the socket, and the second wrote into the freed object:
BUG: KASAN: slab-use-after-free in refcount_warn_saturate
Write of size 4 at addr ffff88800b1cac80 by task kworker
Workqueue: events vsock_pending_work
Treat peer RST like any other unexpected packet type (err = -EINVAL).
All destroy: arms now return err < 0, so vmci_transport_recv_listen()
removes pending from pending_links synchronously and
vsock_pending_work() takes the is_pending=false / !rejected branch,
dropping only its own work reference. This also closes the
multi-packet race Sashiko reported on v2: pending is removed from
the list before any subsequent packet can find it.
The pre-existing sk_acceptq_removed() gap on the err < 0 path of
vmci_transport_recv_listen() that Sashiko also noted is not
introduced or changed by this patch.
Tested on lts-6.12.79 with KASAN: 52/100 unpatched -> 0/100 patched.
CVSS Score
8.8
EPSS Score
0.001
Published
2026-07-19