Linux: >> Linux Kernel >> 6.1.43 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: check for station first in client probe
When probing a client, first check if we have it, and then
check for the channel context, otherwise you can trigger
the warning there easily by probing when the AP isn't even
started yet. Since a client existing means the AP is also
operating, we can then keep the warning.
Also simplify the moved code a bit.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
cifs: Release folio lock on fscache read hit.
Under the current code, when cifs_readpage_worker is called, the call
contract is that the callee should unlock the page. This is documented
in the read_folio section of Documentation/filesystems/vfs.rst as:
> The filesystem should unlock the folio once the read has completed,
> whether it was successful or not.
Without this change, when fscache is in use and cache hit occurs during
a read, the page lock is leaked, producing the following stack on
subsequent reads (via mmap) to the page:
$ cat /proc/3890/task/12864/stack
[<0>] folio_wait_bit_common+0x124/0x350
[<0>] filemap_read_folio+0xad/0xf0
[<0>] filemap_fault+0x8b1/0xab0
[<0>] __do_fault+0x39/0x150
[<0>] do_fault+0x25c/0x3e0
[<0>] __handle_mm_fault+0x6ca/0xc70
[<0>] handle_mm_fault+0xe9/0x350
[<0>] do_user_addr_fault+0x225/0x6c0
[<0>] exc_page_fault+0x84/0x1b0
[<0>] asm_exc_page_fault+0x27/0x30
This requires a reboot to resolve; it is a deadlock.
Note however that the call to cifs_readpage_from_fscache does mark the
page clean, but does not free the folio lock. This happens in
__cifs_readpage_from_fscache on success. Releasing the lock at that
point however is not appropriate as cifs_readahead also calls
cifs_readpage_from_fscache and *does* unconditionally release the lock
after its return. This change therefore effectively makes
cifs_readpage_worker work like cifs_readahead.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
bpf: reject unhashed sockets in bpf_sk_assign
The semantics for bpf_sk_assign are as follows:
sk = some_lookup_func()
bpf_sk_assign(skb, sk)
bpf_sk_release(sk)
That is, the sk is not consumed by bpf_sk_assign. The function
therefore needs to make sure that sk lives long enough to be
consumed from __inet_lookup_skb. The path through the stack for a
TCPv4 packet is roughly:
netif_receive_skb_core: takes RCU read lock
__netif_receive_skb_core:
sch_handle_ingress:
tcf_classify:
bpf_sk_assign()
deliver_ptype_list_skb:
deliver_skb:
ip_packet_type->func == ip_rcv:
ip_rcv_core:
ip_rcv_finish_core:
dst_input:
ip_local_deliver:
ip_local_deliver_finish:
ip_protocol_deliver_rcu:
tcp_v4_rcv:
__inet_lookup_skb:
skb_steal_sock
The existing helper takes advantage of the fact that everything
happens in the same RCU critical section: for sockets with
SOCK_RCU_FREE set bpf_sk_assign never takes a reference.
skb_steal_sock then checks SOCK_RCU_FREE again and does sock_put
if necessary.
This approach assumes that SOCK_RCU_FREE is never set on a sk
between bpf_sk_assign and skb_steal_sock, but this invariant is
violated by unhashed UDP sockets. A new UDP socket is created
in TCP_CLOSE state but without SOCK_RCU_FREE set. That flag is only
added in udp_lib_get_port() which happens when a socket is bound.
When bpf_sk_assign was added it wasn't possible to access unhashed
UDP sockets from BPF, so this wasn't a problem. This changed
in commit 0c48eefae712 ("sock_map: Lift socket state restriction
for datagram sockets"), but the helper wasn't adjusted accordingly.
The following sequence of events will therefore lead to a refcount
leak:
1. Add socket(AF_INET, SOCK_DGRAM) to a sockmap.
2. Pull socket out of sockmap and bpf_sk_assign it. Since
SOCK_RCU_FREE is not set we increment the refcount.
3. bind() or connect() the socket, setting SOCK_RCU_FREE.
4. skb_steal_sock will now set refcounted = false due to
SOCK_RCU_FREE.
5. tcp_v4_rcv() skips sock_put().
Fix the problem by rejecting unhashed sockets in bpf_sk_assign().
This matches the behaviour of __inet_lookup_skb which is ultimately
the goal of bpf_sk_assign().
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
wifi: rtw88: delete timer and free skb queue when unloading
Fix possible crash and memory leak on driver unload by deleting
TX purge timer and freeing C2H queue in 'rtw_core_deinit()',
shrink critical section in the latter by freeing COEX queue
out of TX report lock scope.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
bpf, cpumap: Make sure kthread is running before map update returns
The following warning was reported when running stress-mode enabled
xdp_redirect_cpu with some RT threads:
------------[ cut here ]------------
WARNING: CPU: 4 PID: 65 at kernel/bpf/cpumap.c:135
CPU: 4 PID: 65 Comm: kworker/4:1 Not tainted 6.5.0-rc2+ #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
Workqueue: events cpu_map_kthread_stop
RIP: 0010:put_cpu_map_entry+0xda/0x220
......
Call Trace:
<TASK>
? show_regs+0x65/0x70
? __warn+0xa5/0x240
......
? put_cpu_map_entry+0xda/0x220
cpu_map_kthread_stop+0x41/0x60
process_one_work+0x6b0/0xb80
worker_thread+0x96/0x720
kthread+0x1a5/0x1f0
ret_from_fork+0x3a/0x70
ret_from_fork_asm+0x1b/0x30
</TASK>
The root cause is the same as commit 436901649731 ("bpf: cpumap: Fix memory
leak in cpu_map_update_elem"). The kthread is stopped prematurely by
kthread_stop() in cpu_map_kthread_stop(), and kthread() doesn't call
cpu_map_kthread_run() at all but XDP program has already queued some
frames or skbs into ptr_ring. So when __cpu_map_ring_cleanup() checks
the ptr_ring, it will find it was not emptied and report a warning.
An alternative fix is to use __cpu_map_ring_cleanup() to drop these
pending frames or skbs when kthread_stop() returns -EINTR, but it may
confuse the user, because these frames or skbs have been handled
correctly by XDP program. So instead of dropping these frames or skbs,
just make sure the per-cpu kthread is running before
__cpu_map_entry_alloc() returns.
After apply the fix, the error handle for kthread_stop() will be
unnecessary because it will always return 0, so just remove it.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
USB: Gadget: core: Help prevent panic during UVC unconfigure
Avichal Rakesh reported a kernel panic that occurred when the UVC
gadget driver was removed from a gadget's configuration. The panic
involves a somewhat complicated interaction between the kernel driver
and a userspace component (as described in the Link tag below), but
the analysis did make one thing clear: The Gadget core should
accomodate gadget drivers calling usb_gadget_deactivate() as part of
their unbind procedure.
Currently this doesn't work. gadget_unbind_driver() calls
driver->unbind() while holding the udc->connect_lock mutex, and
usb_gadget_deactivate() attempts to acquire that mutex, which will
result in a deadlock.
The simple fix is for gadget_unbind_driver() to release the mutex when
invoking the ->unbind() callback. There is no particular reason for
it to be holding the mutex at that time, and the mutex isn't held
while the ->bind() callback is invoked. So we'll drop the mutex
before performing the unbind callback and reacquire it afterward.
We'll also add a couple of comments to usb_gadget_activate() and
usb_gadget_deactivate(). Because they run in process context they
must not be called from a gadget driver's ->disconnect() callback,
which (according to the kerneldoc for struct usb_gadget_driver in
include/linux/usb/gadget.h) may run in interrupt context. This may
help prevent similar bugs from arising in the future.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
s390/zcrypt: don't leak memory if dev_set_name() fails
When dev_set_name() fails, zcdn_create() doesn't free the newly
allocated resources. Do it.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
wifi: nl80211: fix integer overflow in nl80211_parse_mbssid_elems()
nl80211_parse_mbssid_elems() uses a u8 variable num_elems to count the
number of MBSSID elements in the nested netlink attribute attrs, which can
lead to an integer overflow if a user of the nl80211 interface specifies
256 or more elements in the corresponding attribute in userspace. The
integer overflow can lead to a heap buffer overflow as num_elems determines
the size of the trailing array in elems, and this array is thereafter
written to for each element in attrs.
Note that this vulnerability only affects devices with the
wiphy->mbssid_max_interfaces member set for the wireless physical device
struct in the device driver, and can only be triggered by a process with
CAP_NET_ADMIN capabilities.
Fix this by checking for a maximum of 255 elements in attrs.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
ip_vti: fix potential slab-use-after-free in decode_session6
When ip_vti device is set to the qdisc of the sfb type, the cb field
of the sent skb may be modified during enqueuing. Then,
slab-use-after-free may occur when ip_vti device sends IPv6 packets.
As commit f855691975bb ("xfrm6: Fix the nexthdr offset in
_decode_session6.") showed, xfrm_decode_session was originally intended
only for the receive path. IP6CB(skb)->nhoff is not set during
transmission. Therefore, set the cb field in the skb to 0 before
sending packets.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-10-04
In the Linux kernel, the following vulnerability has been resolved:
net: usbnet: Fix WARNING in usbnet_start_xmit/usb_submit_urb
The syzbot fuzzer identified a problem in the usbnet driver:
usb 1-1: BOGUS urb xfer, pipe 3 != type 1
WARNING: CPU: 0 PID: 754 at drivers/usb/core/urb.c:504 usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504
Modules linked in:
CPU: 0 PID: 754 Comm: kworker/0:2 Not tainted 6.4.0-rc7-syzkaller-00014-g692b7dc87ca6 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
Workqueue: mld mld_ifc_work
RIP: 0010:usb_submit_urb+0xed6/0x1880 drivers/usb/core/urb.c:504
Code: 7c 24 18 e8 2c b4 5b fb 48 8b 7c 24 18 e8 42 07 f0 fe 41 89 d8 44 89 e1 4c 89 ea 48 89 c6 48 c7 c7 a0 c9 fc 8a e8 5a 6f 23 fb <0f> 0b e9 58 f8 ff ff e8 fe b3 5b fb 48 81 c5 c0 05 00 00 e9 84 f7
RSP: 0018:ffffc9000463f568 EFLAGS: 00010086
RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000000
RDX: ffff88801eb28000 RSI: ffffffff814c03b7 RDI: 0000000000000001
RBP: ffff8881443b7190 R08: 0000000000000001 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000001 R12: 0000000000000003
R13: ffff88802a77cb18 R14: 0000000000000003 R15: ffff888018262500
FS: 0000000000000000(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000556a99c15a18 CR3: 0000000028c71000 CR4: 0000000000350ef0
Call Trace:
<TASK>
usbnet_start_xmit+0xfe5/0x2190 drivers/net/usb/usbnet.c:1453
__netdev_start_xmit include/linux/netdevice.h:4918 [inline]
netdev_start_xmit include/linux/netdevice.h:4932 [inline]
xmit_one net/core/dev.c:3578 [inline]
dev_hard_start_xmit+0x187/0x700 net/core/dev.c:3594
...
This bug is caused by the fact that usbnet trusts the bulk endpoint
addresses its probe routine receives in the driver_info structure, and
it does not check to see that these endpoints actually exist and have
the expected type and directions.
The fix is simply to add such a check.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-10-04