Linux: >> Linux Kernel >> 6.12.12 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
x86/ftrace: Relocate %rip-relative percpu refs in dynamic trampolines
With CONFIG_CALL_DEPTH_TRACKING enabled on an x86 retbleed-affected platform
(eg: Skylake), with retbleed=stuff, registering a dynamic ftrace trampoline
crashes on the first call into the traced function:
BUG: unable to handle page fault for address: ffff88817ae18880
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
PGD 4b53067 P4D 4b53067 PUD 0
Oops: Oops: 0002 [#1] SMP PTI
CPU: 3 UID: 0 PID: 187 Comm: usleep Not tainted 7.0.10 #243 PREEMPT(full)
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014
Code: 24 78 00 00 00 00 48 89 ea 48 89 54 24 20 48 8b b4 24 b8 00 00 00 48 8b bc 24 b0 00 00 00 48 89 bc 24 80 00 00 00 48 83 ef 05 <65> 48 c1 3d 1f a8 b6 02 05 48 8b 15 f6 00 00 00 4c 89 3c 24 4c 89
Call Trace:
<TASK>
? find_held_lock
? exc_page_fault
? lock_release
? __x64_sys_clock_nanosleep
? lockdep_hardirqs_on_prepare
? trace_hardirqs_on
__x64_sys_clock_nanosleep
do_syscall_64
? exc_page_fault
? call_depth_return_thunk
entry_SYSCALL_64_after_hwframe
...
Kernel panic - not syncing: Fatal exception
This small reproducer allows to easily trigger the crash:
# echo 'p __x64_sys_clock_nanosleep' > /sys/kernel/tracing/kprobe_events
# echo 1 > /sys/kernel/tracing/events/kprobes/p___x64_sys_clock_nanosleep_0/enable
# usleep 1
Monitoring the crash under GDB points to the exact instruction in charge of
incrementing the call depth:
sarq $5, %gs:__x86_call_depth(%rip)
This instruction matches the one inserted by the ftrace_regs_caller from
ftrace_64.S. This emitted code was likely working fine until the introduction
of
59bec00ace28 ("x86/percpu: Introduce %rip-relative addressing to PER_CPU_VAR()"):
it has made the call depth accounting addressing relative to $rip, instead of
being based on an absolute address.
As this code exact location depends on where the trampoline lives in memory,
the corresponding displacement needs to be adjusted at runtime to actually
correctly find the per-cpu __x86_call_depth value, otherwise the targeted
address is wrong, leading to the page fault seen above.
Fix the %rip-relative displacement of the copied CALL_DEPTH_ACCOUNT
instruction (from ftrace_regs_caller) by calling text_poke_apply_relocation(),
as it is done for example by the x86 BPF JIT compiler through
x86_call_depth_emit_accounting(). This corrects both CALL_DEPTH_ACCOUNT slots,
in ftrace_caller and ftrace_regs_caller.
[ bp: Massage. ]
CVSS Score
8.1
EPSS Score
0.003
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
Input: elan_i2c - validate firmware size before use
Ensure that the firmware file is large enough to contain the expected
number of pages and the signature (which resides at the end of the
firmware blob) before accessing them to prevent potential out-of-bounds
reads.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
octeontx2-af: CGX: add bounds check to cgx_speed_mbps index
cgx_speed_mbps has 13 elements but RESP_LINKSTAT_SPEED can yield values
0-15. If it returns a value >= 13, this causes an out-of-bounds array
access. Add a bounds check and default to speed 0 if the index is out of
range.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
sched_ext: Avoid UAF in scx_root_enable_workfn() init failure path
In scx_root_enable_workfn(), put_task_struct(p) is called before scx_error()
dereferences p->comm and p->pid. If the iterator's reference is the last
drop, the task is freed synchronously and the deref becomes a UAF.
Move put_task_struct() past scx_error().
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
ACPI: driver: Check ACPI_COMPANION() against NULL during probe
Since every platform driver can be forced to match a device that doesn't
match its list of device IDs because of device_match_driver_override(),
platform drivers that rely on the existence of a device's ACPI companion
object should verify its presence.
Accordingly, add requisite ACPI_COMPANION() or ACPI_HANDLE() checks
against NULL to 13 platform drivers handling core ACPI devices.
Also change the value returned by the ACPI thermal zone driver when
the device's ACPI companion is not present to -ENODEV for consistency
with the other drivers.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
octeontx2-pf: avoid double free of pool->stack on AQ init failure
otx2_pool_aq_init() frees pool->stack when mailbox sync or retry
allocation fails, but leaves the pointer unchanged. Later,
otx2_sq_aura_pool_init() unwinds the partial setup through
otx2_aura_pool_free(), which frees pool->stack again. The CN20K-specific
cn20k_pool_aq_init() implementation has the same bug in
its corresponding error path.
Set pool->stack to NULL immediately after the local free so the shared
cleanup path does not free the same stack again while cleaning up
partially initialized pool state.
The bug was first flagged by an experimental analysis tool we are
developing for kernel memory-management bugs while analyzing
v6.13-rc1. The tool is still under development and is not yet publicly
available. Manual inspection confirms that the bug is still present in
v7.1-rc3.
Runtime validation was not performed because reproducing this path
requires OcteonTX2/CN20K hardware.
CVSS Score
7.0
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: consume only present negotiated TTLM maps
ieee80211_tid_to_link_map_size_ok() validates negotiated TTLM elements
against the number of link-map entries indicated by link_map_presence.
ieee80211_parse_neg_ttlm() must consume the same layout.
The parser advanced its cursor for every TID, including TIDs whose
presence bit is clear and therefore have no map bytes in the element.
A sparse map can then make a later present TID read past the validated
element.
The bad bytes land in neg_ttlm->{up,down}link[tid] but are gated by
valid_links before being applied to driver state, so a peer cannot
turn the read into a policy change. Under KUnit + KASAN with an
exact-sized element allocation the OOB read is reported as a
slab-out-of-bounds; whether the same trigger fires under the
production RX path depends on surrounding allocator state.
Advance the cursor only when the current TID has a map present.
CVSS Score
8.1
EPSS Score
0.003
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
powerpc/time: Remove redundant preempt_disable|enable() calls from arch_irq_work_raise()
A kernel panic is observed when handling machine check exceptions from
real mode.
BUG: Unable to handle kernel data access on read at 0xc00000006be21300
Oops: Kernel access of bad area, sig: 11 [#1]
MSR: 8000000000001003 <SF,ME,RI,LE> CR: 88222248 XER: 00000005
CFAR: c00000000003ffc4 DAR: c00000006be21300 DSISR: 40000000 IRQMASK: 0
NIP [c000000000029e40] arch_irq_work_raise+0x10/0x70
LR [c00000000003ffc8] machine_check_queue_event+0xa8/0x150
Call Trace:
[c0000000179d3c70] [c00000000003ff64] machine_check_queue_event+0x44/0x150
[c0000000179d3d30] [c0000000000084e0] machine_check_early_common+0x1f0/0x2c0
The crash occurs because arch_irq_work_raise() calls preempt_disable()
from machine check exception (MCE) handlers running in real mode. In
this context, accessing the preempt_count can fault, leading to the panic.
The preempt_disable()/preempt_enable() pair in arch_irq_work_raise()
was originally added by commit 0fe1ac48bef0 ("powerpc/perf_event: Fix
oops due to perf_event_do_pending call") to avoid races while raising
irq work from exception context.
Later, commit 471ba0e686cb ("irq_work: Do not raise an IPI when
queueing work on the local CPU") added preemption protection in
irq_work_queue() path, while commit 20b876918c06 ("irq_work: Use per
cpu atomics instead of regular atomics") added equivalent
protection in irq_work_queue_on() before reaching arch_irq_work_raise():
irq_work_queue() / irq_work_queue_on()
-> preempt_disable()
-> __irq_work_queue_local()
-> irq_work_raise()
-> arch_irq_work_raise()
As a result, callers other than mce_irq_work_raise() already execute
with preemption disabled, making the additional
preempt_disable()/preempt_enable() pair in arch_irq_work_raise()
redundant.
The arch_irq_work_raise() function executes in NMI context when called
from MCE handler. Hence we will not be preempted or scheduled out since
we are in NMI context with MSR[EE]=0. Therefore, it is safe to remove
the preempt_disable()/preempt_enable() calls from here.
Remove it to avoid accessing preempt_count from real mode context.
[Maddy: Fixed the commit title]
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix potential UAF in netfs_unlock_abandoned_read_pages()
netfs_unlock_abandoned_read_pages(rreq) accesses the index of the folios it
is wanting to unlock and compares that to rreq->no_unlock_folio so that it
doesn't unlock a folio being read for netfs_perform_write() or
netfs_write_begin().
However, given that netfs_unlock_abandoned_read_pages() is called _after_
NETFS_RREQ_IN_PROGRESS is cleared, the one folio that it's not allowed to
dereference is the one specified by ->no_unlock_folio as ownership
immediately reverts to the caller.
Fix this by storing the folio pointer instead and using that rather than
the index. Also fix netfs_unlock_read_folio() where the same applies.
CVSS Score
9.8
EPSS Score
0.004
Published
2026-07-24
In the Linux kernel, the following vulnerability has been resolved:
netfs: Fix overrun check in netfs_extract_user_iter()
Fix netfs_extract_user_iter() so that if iov_iter_extract_pages() overfills
pages[], then those pages don't get included in the iterator constructed at
the end of the function. If there was an overfill, memory corruption has
already happened.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-07-24