Linux: >> Linux Kernel >> 6.6.62 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
net_sched: ets: fix a race in ets_qdisc_change()
Gerrard Tai reported a race condition in ETS, whenever SFQ perturb timer
fires at the wrong time.
The race is as follows:
CPU 0 CPU 1
[1]: lock root
[2]: qdisc_tree_flush_backlog()
[3]: unlock root
|
| [5]: lock root
| [6]: rehash
| [7]: qdisc_tree_reduce_backlog()
|
[4]: qdisc_put()
This can be abused to underflow a parent's qlen.
Calling qdisc_purge_queue() instead of qdisc_tree_flush_backlog()
should fix the race, because all packets will be purged from the qdisc
before releasing the lock.
CVSS Score
7.0
EPSS Score
0.0
Published
2025-07-03
In the Linux kernel, the following vulnerability has been resolved:
net_sched: red: fix a race in __red_change()
Gerrard Tai reported a race condition in RED, whenever SFQ perturb timer
fires at the wrong time.
The race is as follows:
CPU 0 CPU 1
[1]: lock root
[2]: qdisc_tree_flush_backlog()
[3]: unlock root
|
| [5]: lock root
| [6]: rehash
| [7]: qdisc_tree_reduce_backlog()
|
[4]: qdisc_put()
This can be abused to underflow a parent's qlen.
Calling qdisc_purge_queue() instead of qdisc_tree_flush_backlog()
should fix the race, because all packets will be purged from the qdisc
before releasing the lock.
CVSS Score
7.0
EPSS Score
0.0
Published
2025-07-03
In the Linux kernel, the following vulnerability has been resolved:
net/mlx5: Fix ECVF vports unload on shutdown flow
Fix shutdown flow UAF when a virtual function is created on the embedded
chip (ECVF) of a BlueField device. In such case the vport acl ingress
table is not properly destroyed.
ECVF functionality is independent of ecpf_vport_exists capability and
thus functions mlx5_eswitch_(enable|disable)_pf_vf_vports() should not
test it when enabling/disabling ECVF vports.
kernel log:
[] refcount_t: underflow; use-after-free.
[] WARNING: CPU: 3 PID: 1 at lib/refcount.c:28
refcount_warn_saturate+0x124/0x220
----------------
[] Call trace:
[] refcount_warn_saturate+0x124/0x220
[] tree_put_node+0x164/0x1e0 [mlx5_core]
[] mlx5_destroy_flow_table+0x98/0x2c0 [mlx5_core]
[] esw_acl_ingress_table_destroy+0x28/0x40 [mlx5_core]
[] esw_acl_ingress_lgcy_cleanup+0x80/0xf4 [mlx5_core]
[] esw_legacy_vport_acl_cleanup+0x44/0x60 [mlx5_core]
[] esw_vport_cleanup+0x64/0x90 [mlx5_core]
[] mlx5_esw_vport_disable+0xc0/0x1d0 [mlx5_core]
[] mlx5_eswitch_unload_ec_vf_vports+0xcc/0x150 [mlx5_core]
[] mlx5_eswitch_disable_sriov+0x198/0x2a0 [mlx5_core]
[] mlx5_device_disable_sriov+0xb8/0x1e0 [mlx5_core]
[] mlx5_sriov_detach+0x40/0x50 [mlx5_core]
[] mlx5_unload+0x40/0xc4 [mlx5_core]
[] mlx5_unload_one_devl_locked+0x6c/0xe4 [mlx5_core]
[] mlx5_unload_one+0x3c/0x60 [mlx5_core]
[] shutdown+0x7c/0xa4 [mlx5_core]
[] pci_device_shutdown+0x3c/0xa0
[] device_shutdown+0x170/0x340
[] __do_sys_reboot+0x1f4/0x2a0
[] __arm64_sys_reboot+0x2c/0x40
[] invoke_syscall+0x78/0x100
[] el0_svc_common.constprop.0+0x54/0x184
[] do_el0_svc+0x30/0xac
[] el0_svc+0x48/0x160
[] el0t_64_sync_handler+0xa4/0x12c
[] el0t_64_sync+0x1a4/0x1a8
[] --[ end trace 9c4601d68c70030e ]---
CVSS Score
7.8
EPSS Score
0.0
Published
2025-07-03
In the Linux kernel, the following vulnerability has been resolved:
net/mdiobus: Fix potential out-of-bounds clause 45 read/write access
When using publicly available tools like 'mdio-tools' to read/write data
from/to network interface and its PHY via C45 (clause 45) mdiobus,
there is no verification of parameters passed to the ioctl and
it accepts any mdio address.
Currently there is support for 32 addresses in kernel via PHY_MAX_ADDR define,
but it is possible to pass higher value than that via ioctl.
While read/write operation should generally fail in this case,
mdiobus provides stats array, where wrong address may allow out-of-bounds
read/write.
Fix that by adding address verification before C45 read/write operation.
While this excludes this access from any statistics, it improves security of
read/write operation.
CVSS Score
7.1
EPSS Score
0.0
Published
2025-07-03
In the Linux kernel, the following vulnerability has been resolved:
net/mdiobus: Fix potential out-of-bounds read/write access
When using publicly available tools like 'mdio-tools' to read/write data
from/to network interface and its PHY via mdiobus, there is no verification of
parameters passed to the ioctl and it accepts any mdio address.
Currently there is support for 32 addresses in kernel via PHY_MAX_ADDR define,
but it is possible to pass higher value than that via ioctl.
While read/write operation should generally fail in this case,
mdiobus provides stats array, where wrong address may allow out-of-bounds
read/write.
Fix that by adding address verification before read/write operation.
While this excludes this access from any statistics, it improves security of
read/write operation.
CVSS Score
7.1
EPSS Score
0.0
Published
2025-07-03
In the Linux kernel, the following vulnerability has been resolved:
net: Fix TOCTOU issue in sk_is_readable()
sk->sk_prot->sock_is_readable is a valid function pointer when sk resides
in a sockmap. After the last sk_psock_put() (which usually happens when
socket is removed from sockmap), sk->sk_prot gets restored and
sk->sk_prot->sock_is_readable becomes NULL.
This makes sk_is_readable() racy, if the value of sk->sk_prot is reloaded
after the initial check. Which in turn may lead to a null pointer
dereference.
Ensure the function pointer does not turn NULL after the check.
CVSS Score
4.7
EPSS Score
0.0
Published
2025-07-03
In the Linux kernel, the following vulnerability has been resolved:
espintcp: remove encap socket caching to avoid reference leak
The current scheme for caching the encap socket can lead to reference
leaks when we try to delete the netns.
The reference chain is: xfrm_state -> enacp_sk -> netns
Since the encap socket is a userspace socket, it holds a reference on
the netns. If we delete the espintcp state (through flush or
individual delete) before removing the netns, the reference on the
socket is dropped and the netns is correctly deleted. Otherwise, the
netns may not be reachable anymore (if all processes within the ns
have terminated), so we cannot delete the xfrm state to drop its
reference on the socket.
This patch results in a small (~2% in my tests) performance
regression.
A GC-type mechanism could be added for the socket cache, to clear
references if the state hasn't been used "recently", but it's a lot
more complex than just not caching the socket.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-07-03
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: Disable SCO support if READ_VOICE_SETTING is unsupported/broken
A SCO connection without the proper voice_setting can cause
the controller to lock up.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-07-03
In the Linux kernel, the following vulnerability has been resolved:
x86/iopl: Cure TIF_IO_BITMAP inconsistencies
io_bitmap_exit() is invoked from exit_thread() when a task exists or
when a fork fails. In the latter case the exit_thread() cleans up
resources which were allocated during fork().
io_bitmap_exit() invokes task_update_io_bitmap(), which in turn ends up
in tss_update_io_bitmap(). tss_update_io_bitmap() operates on the
current task. If current has TIF_IO_BITMAP set, but no bitmap installed,
tss_update_io_bitmap() crashes with a NULL pointer dereference.
There are two issues, which lead to that problem:
1) io_bitmap_exit() should not invoke task_update_io_bitmap() when
the task, which is cleaned up, is not the current task. That's a
clear indicator for a cleanup after a failed fork().
2) A task should not have TIF_IO_BITMAP set and neither a bitmap
installed nor IOPL emulation level 3 activated.
This happens when a kernel thread is created in the context of
a user space thread, which has TIF_IO_BITMAP set as the thread
flags are copied and the IO bitmap pointer is cleared.
Other than in the failed fork() case this has no impact because
kernel threads including IO workers never return to user space and
therefore never invoke tss_update_io_bitmap().
Cure this by adding the missing cleanups and checks:
1) Prevent io_bitmap_exit() to invoke task_update_io_bitmap() if
the to be cleaned up task is not the current task.
2) Clear TIF_IO_BITMAP in copy_thread() unconditionally. For user
space forks it is set later, when the IO bitmap is inherited in
io_bitmap_share().
For paranoia sake, add a warning into tss_update_io_bitmap() to catch
the case, when that code is invoked with inconsistent state.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-07-03
In the Linux kernel, the following vulnerability has been resolved:
VMCI: fix race between vmci_host_setup_notify and vmci_ctx_unset_notify
During our test, it is found that a warning can be trigger in try_grab_folio
as follow:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 1678 at mm/gup.c:147 try_grab_folio+0x106/0x130
Modules linked in:
CPU: 0 UID: 0 PID: 1678 Comm: syz.3.31 Not tainted 6.15.0-rc5 #163 PREEMPT(undef)
RIP: 0010:try_grab_folio+0x106/0x130
Call Trace:
<TASK>
follow_huge_pmd+0x240/0x8e0
follow_pmd_mask.constprop.0.isra.0+0x40b/0x5c0
follow_pud_mask.constprop.0.isra.0+0x14a/0x170
follow_page_mask+0x1c2/0x1f0
__get_user_pages+0x176/0x950
__gup_longterm_locked+0x15b/0x1060
? gup_fast+0x120/0x1f0
gup_fast_fallback+0x17e/0x230
get_user_pages_fast+0x5f/0x80
vmci_host_unlocked_ioctl+0x21c/0xf80
RIP: 0033:0x54d2cd
---[ end trace 0000000000000000 ]---
Digging into the source, context->notify_page may init by get_user_pages_fast
and can be seen in vmci_ctx_unset_notify which will try to put_page. However
get_user_pages_fast is not finished here and lead to following
try_grab_folio warning. The race condition is shown as follow:
cpu0 cpu1
vmci_host_do_set_notify
vmci_host_setup_notify
get_user_pages_fast(uva, 1, FOLL_WRITE, &context->notify_page);
lockless_pages_from_mm
gup_pgd_range
gup_huge_pmd // update &context->notify_page
vmci_host_do_set_notify
vmci_ctx_unset_notify
notify_page = context->notify_page;
if (notify_page)
put_page(notify_page); // page is freed
__gup_longterm_locked
__get_user_pages
follow_trans_huge_pmd
try_grab_folio // warn here
To slove this, use local variable page to make notify_page can be seen
after finish get_user_pages_fast.
CVSS Score
7.0
EPSS Score
0.0
Published
2025-07-03