Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
net/sched: Enforce that teql can only be used as root qdisc
Design intent of teql is that it is only supposed to be used as root qdisc.
We need to check for that constraint.
Although not important, I will describe the scenario that unearthed this
issue for the curious.
GangMin Kim <km.kim1503@gmail.com> managed to concot a scenario as follows:
ROOT qdisc 1:0 (QFQ)
├── class 1:1 (weight=15, lmax=16384) netem with delay 6.4s
└── class 1:2 (weight=1, lmax=1514) teql
GangMin sends a packet which is enqueued to 1:1 (netem).
Any invocation of dequeue by QFQ from this class will not return a packet
until after 6.4s. In the meantime, a second packet is sent and it lands on
1:2. teql's enqueue will return success and this will activate class 1:2.
Main issue is that teql only updates the parent visible qlen (sch->q.qlen)
at dequeue. Since QFQ will only call dequeue if peek succeeds (and teql's
peek always returns NULL), dequeue will never be called and thus the qlen
will remain as 0. With that in mind, when GangMin updates 1:2's lmax value,
the qfq_change_class calls qfq_deact_rm_from_agg. Since the child qdisc's
qlen was not incremented, qfq fails to deactivate the class, but still
frees its pointers from the aggregate. So when the first packet is
rescheduled after 6.4 seconds (netem's delay), a dangling pointer is
accessed causing GangMin's causing a UAF.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
can: esd_usb: esd_usb_read_bulk_callback(): fix URB memory leak
Fix similar memory leak as in commit 7352e1d5932a ("can: gs_usb:
gs_usb_receive_bulk_callback(): fix URB memory leak").
In esd_usb_open(), the URBs for USB-in transfers are allocated, added to
the dev->rx_submitted anchor and submitted. In the complete callback
esd_usb_read_bulk_callback(), the URBs are processed and resubmitted. In
esd_usb_close() the URBs are freed by calling
usb_kill_anchored_urbs(&dev->rx_submitted).
However, this does not take into account that the USB framework unanchors
the URB before the complete function is called. This means that once an
in-URB has been completed, it is no longer anchored and is ultimately not
released in esd_usb_close().
Fix the memory leak by anchoring the URB in the
esd_usb_read_bulk_callback() to the dev->rx_submitted anchor.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
ALSA: ctxfi: Fix potential OOB access in audio mixer handling
In the audio mixer handling code of ctxfi driver, the conf field is
used as a kind of loop index, and it's referred in the index callbacks
(amixer_index() and sum_index()).
As spotted recently by fuzzers, the current code causes OOB access at
those functions.
| UBSAN: array-index-out-of-bounds in /build/reproducible-path/linux-6.17.8/sound/pci/ctxfi/ctamixer.c:347:48
| index 8 is out of range for type 'unsigned char [8]'
After the analysis, the cause was found to be the lack of the proper
(re-)initialization of conj field.
This patch addresses those OOB accesses by adding the proper
initializations of the loop indices.
CVSS Score
7.1
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted merge
Patch series "mm/vma: fix anon_vma UAF on mremap() faulted, unfaulted
merge", v2.
Commit 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA
merges") introduced the ability to merge previously unavailable VMA merge
scenarios.
However, it is handling merges incorrectly when it comes to mremap() of a
faulted VMA adjacent to an unfaulted VMA. The issues arise in three
cases:
1. Previous VMA unfaulted:
copied -----|
v
|-----------|.............|
| unfaulted |(faulted VMA)|
|-----------|.............|
prev
2. Next VMA unfaulted:
copied -----|
v
|.............|-----------|
|(faulted VMA)| unfaulted |
|.............|-----------|
next
3. Both adjacent VMAs unfaulted:
copied -----|
v
|-----------|.............|-----------|
| unfaulted |(faulted VMA)| unfaulted |
|-----------|.............|-----------|
prev next
This series fixes each of these cases, and introduces self tests to assert
that the issues are corrected.
I also test a further case which was already handled, to assert that my
changes continues to correctly handle it:
4. prev unfaulted, next faulted:
copied -----|
v
|-----------|.............|-----------|
| unfaulted |(faulted VMA)| faulted |
|-----------|.............|-----------|
prev next
This bug was discovered via a syzbot report, linked to in the first patch
in the series, I confirmed that this series fixes the bug.
I also discovered that we are failing to check that the faulted VMA was
not forked when merging a copied VMA in cases 1-3 above, an issue this
series also addresses.
I also added self tests to assert that this is resolved (and confirmed
that the tests failed prior to this).
I also cleaned up vma_expand() as part of this work, renamed
vma_had_uncowed_parents() to vma_is_fork_child() as the previous name was
unduly confusing, and simplified the comments around this function.
This patch (of 4):
Commit 879bca0a2c4f ("mm/vma: fix incorrectly disallowed anonymous VMA
merges") introduced the ability to merge previously unavailable VMA merge
scenarios.
The key piece of logic introduced was the ability to merge a faulted VMA
immediately next to an unfaulted VMA, which relies upon dup_anon_vma() to
correctly handle anon_vma state.
In the case of the merge of an existing VMA (that is changing properties
of a VMA and then merging if those properties are shared by adjacent
VMAs), dup_anon_vma() is invoked correctly.
However in the case of the merge of a new VMA, a corner case peculiar to
mremap() was missed.
The issue is that vma_expand() only performs dup_anon_vma() if the target
(the VMA that will ultimately become the merged VMA): is not the next VMA,
i.e. the one that appears after the range in which the new VMA is to be
established.
A key insight here is that in all other cases other than mremap(), a new
VMA merge either expands an existing VMA, meaning that the target VMA will
be that VMA, or would have anon_vma be NULL.
Specifically:
* __mmap_region() - no anon_vma in place, initial mapping.
* do_brk_flags() - expanding an existing VMA.
* vma_merge_extend() - expanding an existing VMA.
* relocate_vma_down() - no anon_vma in place, initial mapping.
In addition, we are in the unique situation of needing to duplicate
anon_vma state from a VMA that is neither the previous or next VMA being
merged with.
dup_anon_vma() deals exclusively with the target=unfaulted, src=faulted
case. This leaves four possibilities, in each case where the copied VMA
is faulted:
1. Previous VMA unfaulted:
copied -----|
---truncated---
CVSS Score
7.8
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
ALSA: scarlett2: Fix buffer overflow in config retrieval
The scarlett2_usb_get_config() function has a logic error in the
endianness conversion code that can cause buffer overflows when
count > 1.
The code checks `if (size == 2)` where `size` is the total buffer size in
bytes, then loops `count` times treating each element as u16 (2 bytes).
This causes the loop to access `count * 2` bytes when the buffer only
has `size` bytes allocated.
Fix by checking the element size (config_item->size) instead of the
total buffer size. This ensures the endianness conversion matches the
actual element type.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
gpio: cdev: Fix resource leaks on errors in lineinfo_changed_notify()
On error handling paths, lineinfo_changed_notify() doesn't free the
allocated resources which results leaks. Fix it.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
can: mcba_usb: mcba_usb_read_bulk_callback(): fix URB memory leak
Fix similar memory leak as in commit 7352e1d5932a ("can: gs_usb:
gs_usb_receive_bulk_callback(): fix URB memory leak").
In mcba_usb_probe() -> mcba_usb_start(), the URBs for USB-in transfers are
allocated, added to the priv->rx_submitted anchor and submitted. In the
complete callback mcba_usb_read_bulk_callback(), the URBs are processed and
resubmitted. In mcba_usb_close() -> mcba_urb_unlink() the URBs are freed by
calling usb_kill_anchored_urbs(&priv->rx_submitted).
However, this does not take into account that the USB framework unanchors
the URB before the complete function is called. This means that once an
in-URB has been completed, it is no longer anchored and is ultimately not
released in usb_kill_anchored_urbs().
Fix the memory leak by anchoring the URB in the
mcba_usb_read_bulk_callback()to the priv->rx_submitted anchor.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
net: phy: intel-xway: fix OF node refcount leakage
Automated review spotted am OF node reference count leakage when
checking if the 'leds' child node exists.
Call of_put_node() to correctly maintain the refcount.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
net/sched: act_ife: avoid possible NULL deref
tcf_ife_encode() must make sure ife_encode() does not return NULL.
syzbot reported:
Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000: 0000 [#1] SMP KASAN NOPTI
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: 0010:ife_tlv_meta_encode+0x41/0xa0 net/ife/ife.c:166
CPU: 3 UID: 0 PID: 8990 Comm: syz.0.696 Not tainted syzkaller #0 PREEMPT(full)
Call Trace:
<TASK>
ife_encode_meta_u32+0x153/0x180 net/sched/act_ife.c:101
tcf_ife_encode net/sched/act_ife.c:841 [inline]
tcf_ife_act+0x1022/0x1de0 net/sched/act_ife.c:877
tc_act include/net/tc_wrapper.h:130 [inline]
tcf_action_exec+0x1c0/0xa20 net/sched/act_api.c:1152
tcf_exts_exec include/net/pkt_cls.h:349 [inline]
mall_classify+0x1a0/0x2a0 net/sched/cls_matchall.c:42
tc_classify include/net/tc_wrapper.h:197 [inline]
__tcf_classify net/sched/cls_api.c:1764 [inline]
tcf_classify+0x7f2/0x1380 net/sched/cls_api.c:1860
multiq_classify net/sched/sch_multiq.c:39 [inline]
multiq_enqueue+0xe0/0x510 net/sched/sch_multiq.c:66
dev_qdisc_enqueue+0x45/0x250 net/core/dev.c:4147
__dev_xmit_skb net/core/dev.c:4262 [inline]
__dev_queue_xmit+0x2998/0x46c0 net/core/dev.c:4798
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
platform/x86/amd: Fix memory leak in wbrf_record()
The tmp buffer is allocated using kcalloc() but is not freed if
acpi_evaluate_dsm() fails. This causes a memory leak in the error path.
Fix this by explicitly freeing the tmp buffer in the error handling
path of acpi_evaluate_dsm().
CVSS Score
5.5
EPSS Score
0.0
Published
2026-02-04