Linux: >> Linux Kernel >> 6.12.89 Security Vulnerabilities
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
0.001
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
0.001
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
sysfs: don't remove existing directory on update failure
When sysfs_update_group() is called for a named group and create_files()
fails (e.g. -ENOMEM), internal_create_group() calls kernfs_remove(kn) on
the group directory. In the update path, kn was obtained via
kernfs_find_and_get() and refers to a directory that already existed
before this call. Removing it silently destroys a sysfs group that the
caller did not create.
Only remove the directory if we created it ourselves. On update failure
the directory remains as it is left empty by remove_files() inside
create_files(), but can be repopulated by a retry.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
spi: ep93xx: 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 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
0.001
Published
2026-07-19
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
0.001
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
tracing: Do not call map->ops->elt_free() if elt_alloc() fails
In paths where tracing_map_elt_alloc() failed to allocate objects,
the map->ops->elt_alloc() call was never successful. In this case,
map->ops->elt_free() should not be called.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
wifi: cfg80211: advance loop vars in cfg80211_merge_profile()
cfg80211_merge_profile() reassembles a Multi-BSSID non-transmitted BSS
profile that has been split across multiple consecutive MBSSID elements.
Its while-loop calls
cfg80211_get_profile_continuation(ie, ielen, mbssid_elem, sub_elem)
but never advances mbssid_elem or sub_elem inside the body. Each
iteration therefore searches for a continuation that follows the same
fixed pair; the helper returns the same next_mbssid; and the same
next_sub bytes are memcpy()'d into merged_ie at a growing offset until
the buffer fills.
Advance both mbssid_elem and sub_elem to the just-consumed continuation
so the next call to cfg80211_get_profile_continuation() searches for a
further continuation beyond it (or returns NULL when none exists).
A specially-crafted malicious beacon can take advantage of this bug
to cause the kernel to spend an excessive amount of time in
cfg80211_merge_profile (up to as much as 2ms per beacon received),
which could theoretically be abused in some way.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
phonet/pep: disable BH around forwarded sk_receive_skb()
The networking receive path is usually run from softirq context, but
protocols that take the socket lock may have packets stored in the
backlog and processed later from process context. In that case
release_sock() -> __release_sock() drops the slock with spin_unlock_bh()
and then calls sk->sk_backlog_rcv() with bottom halves enabled.
Typical sk_backlog_rcv handlers process the socket whose backlog is
being drained, so the BH state at entry is irrelevant for the slocks
they touch. pep_do_rcv() is different: when the inbound skb targets an
existing PEP pipe, it forwards the skb to a different *child* socket
via sk_receive_skb(). That helper takes the child slock with
bh_lock_sock_nested(), which is just spin_lock_nested() and assumes BH
is already off. The same child slock therefore ends up acquired with
BH on (process path) and with BH off (softirq path):
process context softirq context
--------------- ---------------
release_sock(listener) __netif_receive_skb()
__release_sock() phonet_rcv()
spin_unlock_bh() __sk_receive_skb(listener)
[BH now ENABLED] [BH already disabled]
sk_backlog_rcv: sk_backlog_rcv:
pep_do_rcv() pep_do_rcv()
sk_receive_skb(child) sk_receive_skb(child)
bh_lock_sock_nested(child) bh_lock_sock_nested(child)
=> SOFTIRQ-ON-W => IN-SOFTIRQ-W
Lockdep flags this as inconsistent lock state, and it can become a real
self-deadlock if a softirq on the same CPU tries to receive to the same
child socket while its slock is held in the BH-enabled path:
WARNING: inconsistent lock state
inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
(slock-AF_PHONET/1){+.?.}-{3:3}, at: __sk_receive_skb+0x1cf/0x900
__sk_receive_skb net/core/sock.c:563
sk_receive_skb include/net/sock.h:2022 [inline]
pep_do_rcv net/phonet/pep.c:675
sk_backlog_rcv include/net/sock.h:1190
__release_sock net/core/sock.c:3216
release_sock net/core/sock.c:3815
pep_sock_accept net/phonet/pep.c:879
Wrap the forwarded sk_receive_skb() in local_bh_disable() /
local_bh_enable() so the child slock is always acquired with BH off.
local_bh_disable() nests safely on the softirq path.
Discovered via in-house syzkaller fuzzing; the same root cause also
on the linux-6.1.y syzbot dashboard as extid 44f0626dd6284f02663c.
Reproduced under KASAN + LOCKDEP + PROVE_LOCKING, reproducer:
https://pastebin.com/A3t8xzCR
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
test_kprobes: clear kprobes between test runs
Running the kprobes sanity tests twice makes all tests fail and
eventually crashes the kernel.
[root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run
...
# Totals: pass:5 fail:0 skip:0 total:5
ok 1 kprobes_test
[root@martin-riscv-1 ~]# echo 1 > /sys/kernel/debug/kunit/kprobes_test/run
...
# test_kprobe: EXPECTATION FAILED at lib/tests/test_kprobes.c:64
Expected 0 == register_kprobe(&kp), but
register_kprobe(&kp) == -22 (0xffffffffffffffea)
...
Unable to handle kernel paging request ...
The testsuite defines several kprobes and kretprobes as static variables
that are preserved across test runs.
After register_kprobe and unregister_kprobe, a kprobe contains some
leftover data that must be cleared before the kprobe can be registered
again. The tests are setting symbol_name to define the probe location.
Address and flags must be cleared.
The existing code clears some of the probes between subsequent tests, but
not between two test runs. The leftover data from a previous test run
makes the registrations fail in the next run.
Move the cleanups for all kprobes into kprobes_test_init, this function
is called before each single test (including the first test of a test
run).
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-19
In the Linux kernel, the following vulnerability has been resolved:
btrfs: tracepoints: fix sleep while in atomic context in btrfs_sync_file()
The trace event btrfs_sync_file() is called in an atomic context (all trace
events are) and its call to dput(), which is needed due to the call to
dget_parent(), can sleep, triggering a kernel splat.
This can be reproduced by enabling the trace event and running btrfs/056
from fstests for example. The splat shown in dmesg is the following:
[53.919] BUG: sleeping function called from invalid context at fs/dcache.c:970
[53.947] in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 32773, name: xfs_io
[53.988] preempt_count: 2, expected: 0
[53.967] RCU nest depth: 0, expected: 0
[53.943] Preemption disabled at:
[53.944] [<0000000000000000>] 0x0
[54.078] CPU: 0 UID: 0 PID: 32773 Comm: xfs_io Tainted: G W 7.1.0-rc1-btrfs-next-232+ #1 PREEMPT(full)
[54.070] Tainted: [W]=WARN
[54.071] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.2-0-gea1b7a073390-prebuilt.qemu.org 04/01/2014
[54.072] Call Trace:
[54.074] <TASK>
[54.076] dump_stack_lvl+0x56/0x80
[54.079] __might_resched.cold+0xd6/0x10f
[54.072] dput.part.0+0x24/0x110
[54.078] trace_event_raw_event_btrfs_sync_file+0x75/0x140 [btrfs]
[54.089] btrfs_sync_file+0x1ed/0x530 [btrfs]
[54.087] ? __handle_mm_fault+0x8ae/0xed0
[54.089] btrfs_do_write_iter+0x172/0x210 [btrfs]
[54.091] vfs_write+0x21f/0x450
[54.094] __x64_sys_pwrite64+0x8d/0xc0
[54.096] ? do_user_addr_fault+0x20c/0x670
[54.099] do_syscall_64+0x60/0xf20
[54.092] ? clear_bhb_loop+0x60/0xb0
[54.094] entry_SYSCALL_64_after_hwframe+0x76/0x7e
So stop using dget_parent() and dput() and access the parent dentry
directly as dentry->d_parent. This is also what ext4 is doing in
its equivalent trace event ext4_sync_file_enter().
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-19