Linux: >> Linux Kernel >> 5.1.14 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
vsock/virtio: cap TX credit to local buffer size
The virtio transports derives its TX credit directly from peer_buf_alloc,
which is set from the remote endpoint's SO_VM_SOCKETS_BUFFER_SIZE value.
On the host side this means that the amount of data we are willing to
queue for a connection is scaled by a guest-chosen buffer size, rather
than the host's own vsock configuration. A malicious guest can advertise
a large buffer and read slowly, causing the host to allocate a
correspondingly large amount of sk_buff memory.
The same thing would happen in the guest with a malicious host, since
virtio transports share the same code base.
Introduce a small helper, virtio_transport_tx_buf_size(), that
returns min(peer_buf_alloc, buf_alloc), and use it wherever we consume
peer_buf_alloc.
This ensures the effective TX window is bounded by both the peer's
advertised buffer and our own buf_alloc (already clamped to
buffer_max_size via SO_VM_SOCKETS_BUFFER_MAX_SIZE), so a remote peer
cannot force the other to queue more data than allowed by its own
vsock settings.
On an unpatched Ubuntu 22.04 host (~64 GiB RAM), running a PoC with
32 guest vsock connections advertising 2 GiB each and reading slowly
drove Slab/SUnreclaim from ~0.5 GiB to ~57 GiB; the system only
recovered after killing the QEMU process. That said, if QEMU memory is
limited with cgroups, the maximum memory used will be limited.
With this patch applied:
Before:
MemFree: ~61.6 GiB
Slab: ~142 MiB
SUnreclaim: ~117 MiB
After 32 high-credit connections:
MemFree: ~61.5 GiB
Slab: ~178 MiB
SUnreclaim: ~152 MiB
Only ~35 MiB increase in Slab/SUnreclaim, no host OOM, and the guest
remains responsive.
Compatibility with non-virtio transports:
- VMCI uses the AF_VSOCK buffer knobs to size its queue pairs per
socket based on the local vsk->buffer_* values; the remote side
cannot enlarge those queues beyond what the local endpoint
configured.
- Hyper-V's vsock transport uses fixed-size VMBus ring buffers and
an MTU bound; there is no peer-controlled credit field comparable
to peer_buf_alloc, and the remote endpoint cannot drive in-flight
kernel memory above those ring sizes.
- The loopback path reuses virtio_transport_common.c, so it
naturally follows the same semantics as the virtio transport.
This change is limited to virtio_transport_common.c and thus affects
virtio-vsock, vhost-vsock, and loopback, bringing them in line with the
"remote window intersected with local policy" behaviour that VMCI and
Hyper-V already effectively have.
[Stefano: small adjustments after changing the previous patch]
[Stefano: tweak the commit message]
CVSS Score
5.5
EPSS Score
0.001
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
scsi: xen: scsiback: Fix potential memory leak in scsiback_remove()
Memory allocated for struct vscsiblk_info in scsiback_probe() is not
freed in scsiback_remove() leading to potential memory leaks on remove,
as well as in the scsiback_probe() error paths. Fix that by freeing it
in scsiback_remove().
CVSS Score
5.5
EPSS Score
0.001
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
wifi: rsi: Fix memory corruption due to not set vif driver data size
The struct ieee80211_vif contains trailing space for vif driver data,
when struct ieee80211_vif is allocated, the total memory size that is
allocated is sizeof(struct ieee80211_vif) + size of vif driver data.
The size of vif driver data is set by each WiFi driver as needed.
The RSI911x driver does not set vif driver data size, no trailing space
for vif driver data is therefore allocated past struct ieee80211_vif .
The RSI911x driver does however use the vif driver data to store its
vif driver data structure "struct vif_priv". An access to vif->drv_priv
leads to access out of struct ieee80211_vif bounds and corruption of
some memory.
In case of the failure observed locally, rsi_mac80211_add_interface()
would write struct vif_priv *vif_info = (struct vif_priv *)vif->drv_priv;
vif_info->vap_id = vap_idx. This write corrupts struct fq_tin member
struct list_head new_flows . The flow = list_first_entry(head, struct
fq_flow, flowchain); in fq_tin_reset() then reports non-NULL bogus
address, which when accessed causes a crash.
The trigger is very simple, boot the machine with init=/bin/sh , mount
devtmpfs, sysfs, procfs, and then do "ip link set wlan0 up", "sleep 1",
"ip link set wlan0 down" and the crash occurs.
Fix this by setting the correct size of vif driver data, which is the
size of "struct vif_priv", so that memory is allocated and the driver
can store its driver data in it, instead of corrupting memory around
it.
CVSS Score
7.8
EPSS Score
0.001
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
0.001
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
0.001
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
0.001
Published
2026-02-04
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
0.001
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
0.001
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
rxrpc: Fix recvmsg() unconditional requeue
If rxrpc_recvmsg() fails because MSG_DONTWAIT was specified but the call at
the front of the recvmsg queue already has its mutex locked, it requeues
the call - whether or not the call is already queued. The call may be on
the queue because MSG_PEEK was also passed and so the call was not dequeued
or because the I/O thread requeued it.
The unconditional requeue may then corrupt the recvmsg queue, leading to
things like UAFs or refcount underruns.
Fix this by only requeuing the call if it isn't already on the queue - and
moving it to the front if it is already queued. If we don't queue it, we
have to put the ref we obtained by dequeuing it.
Also, MSG_PEEK doesn't dequeue the call so shouldn't call
rxrpc_notify_socket() for the call if we didn't use up all the data on the
queue, so fix that also.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-02-04
In the Linux kernel, the following vulnerability has been resolved:
spi: spi-sprd-adi: Fix double free in probe error path
The driver currently uses spi_alloc_host() to allocate the controller
but registers it using devm_spi_register_controller().
If devm_register_restart_handler() fails, the code jumps to the
put_ctlr label and calls spi_controller_put(). However, since the
controller was registered via a devm function, the device core will
automatically call spi_controller_put() again when the probe fails.
This results in a double-free of the spi_controller structure.
Fix this by switching to devm_spi_alloc_host() and removing the
manual spi_controller_put() call.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-02-04