Linux: >> Linux Kernel >> 3.4.76 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
comedi: ni_atmio16d: Fix invalid clean-up after failed attach
If the driver's COMEDI "attach" handler function (`atmio16d_attach()`)
returns an error, the COMEDI core will call the driver's "detach"
handler function (`atmio16d_detach()`) to clean up. This calls
`reset_atmio16d()` unconditionally, but depending on where the error
occurred in the attach handler, the device may not have been
sufficiently initialized to call `reset_atmio16d()`. It uses
`dev->iobase` as the I/O port base address and `dev->private` as the
pointer to the COMEDI device's private data structure. `dev->iobase`
may still be set to its initial value of 0, which would result in
undesired writes to low I/O port addresses. `dev->private` may still be
`NULL`, which would result in null pointer dereferences.
Fix `atmio16d_detach()` by checking that `dev->private` is valid
(non-null) before calling `reset_atmio16d()`. This implies that
`dev->iobase` was set correctly since that is set up before
`dev->private`.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
comedi: dt2815: add hardware detection to prevent crash
The dt2815 driver crashes when attached to I/O ports without actual
hardware present. This occurs because syzkaller or users can attach
the driver to arbitrary I/O addresses via COMEDI_DEVCONFIG ioctl.
When no hardware exists at the specified port, inb() operations return
0xff (floating bus), but outb() operations can trigger page faults due
to undefined behavior, especially under race conditions:
BUG: unable to handle page fault for address: 000000007fffff90
#PF: supervisor write access in kernel mode
#PF: error_code(0x0002) - not-present page
RIP: 0010:dt2815_attach+0x6e0/0x1110
Add hardware detection by reading the status register before attempting
any write operations. If the read returns 0xff, assume no hardware is
present and fail the attach with -ENODEV. This prevents crashes from
outb() operations on non-existent hardware.
CVSS Score
4.7
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: u_ether: Fix race between gether_disconnect and eth_stop
A race condition between gether_disconnect() and eth_stop() leads to a
NULL pointer dereference. Specifically, if eth_stop() is triggered
concurrently while gether_disconnect() is tearing down the endpoints,
eth_stop() attempts to access the cleared endpoint descriptor, causing
the following NPE:
Unable to handle kernel NULL pointer dereference
Call trace:
__dwc3_gadget_ep_enable+0x60/0x788
dwc3_gadget_ep_enable+0x70/0xe4
usb_ep_enable+0x60/0x15c
eth_stop+0xb8/0x108
Because eth_stop() crashes while holding the dev->lock, the thread
running gether_disconnect() fails to acquire the same lock and spins
forever, resulting in a hardlockup:
Core - Debugging Information for Hardlockup core(7)
Call trace:
queued_spin_lock_slowpath+0x94/0x488
_raw_spin_lock+0x64/0x6c
gether_disconnect+0x19c/0x1e8
ncm_set_alt+0x68/0x1a0
composite_setup+0x6a0/0xc50
The root cause is that the clearing of dev->port_usb in
gether_disconnect() is delayed until the end of the function.
Move the clearing of dev->port_usb to the very beginning of
gether_disconnect() while holding dev->lock. This cuts off the link
immediately, ensuring eth_stop() will see dev->port_usb as NULL and
safely bail out.
CVSS Score
4.7
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
usb: gadget: f_uac1_legacy: validate control request size
f_audio_complete() copies req->length bytes into a 4-byte stack
variable:
u32 data = 0;
memcpy(&data, req->buf, req->length);
req->length is derived from the host-controlled USB request path,
which can lead to a stack out-of-bounds write.
Validate req->actual against the expected payload size for the
supported control selectors and decode only the expected amount
of data.
This avoids copying a host-influenced length into a fixed-size
stack object.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-01
In the Linux kernel, the following vulnerability has been resolved:
rtnetlink: add missing netlink_ns_capable() check for peer netns
rtnl_newlink() lacks a CAP_NET_ADMIN capability check on the peer
network namespace when creating paired devices (veth, vxcan,
netkit). This allows an unprivileged user with a user namespace
to create interfaces in arbitrary network namespaces, including
init_net.
Add a netlink_ns_capable() check for CAP_NET_ADMIN in the peer
namespace before allowing device creation to proceed.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-04-30
In the Linux kernel, the following vulnerability has been resolved:
gpio: omap: do not register driver in probe()
Commit 11a78b794496 ("ARM: OMAP: MPUIO wake updates") registers the
omap_mpuio_driver from omap_mpuio_init(), which is called from
omap_gpio_probe().
However, it neither makes sense to register drivers from probe()
callbacks of other drivers, nor does the driver core allow registering
drivers with a device lock already being held.
The latter was revealed by commit dc23806a7c47 ("driver core: enforce
device_lock for driver_match_device()") leading to a potential deadlock
condition described in [1].
Additionally, the omap_mpuio_driver is never unregistered from the
driver core, even if the module is unloaded.
Hence, register the omap_mpuio_driver from the module initcall and
unregister it in module_exit().
CVSS Score
5.5
EPSS Score
0.0
Published
2026-04-27
In the Linux kernel, the following vulnerability has been resolved:
driver core: enforce device_lock for driver_match_device()
Currently, driver_match_device() is called from three sites. One site
(__device_attach_driver) holds device_lock(dev), but the other two
(bind_store and __driver_attach) do not. This inconsistency means that
bus match() callbacks are not guaranteed to be called with the lock
held.
Fix this by introducing driver_match_device_locked(), which guarantees
holding the device lock using a scoped guard. Replace the unlocked calls
in bind_store() and __driver_attach() with this new helper. Also add a
lock assertion to driver_match_device() to enforce this guarantee.
This consistency also fixes a known race condition. The driver_override
implementation relies on the device_lock, so the missing lock led to the
use-after-free (UAF) reported in Bugzilla for buses using this field.
Stress testing the two newly locked paths for 24 hours with
CONFIG_PROVE_LOCKING and CONFIG_LOCKDEP enabled showed no UAF recurrence
and no lockdep warnings.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-04-27
In the Linux kernel, the following vulnerability has been resolved:
batman-adv: avoid OGM aggregation when skb tailroom is insufficient
When OGM aggregation state is toggled at runtime, an existing forwarded
packet may have been allocated with only packet_len bytes, while a later
packet can still be selected for aggregation. Appending in this case can
hit skb_put overflow conditions.
Reject aggregation when the target skb tailroom cannot accommodate the new
packet. The caller then falls back to creating a new forward packet
instead of appending.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-04-25
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ip6t_eui64: reject invalid MAC header for all packets
`eui64_mt6()` derives a modified EUI-64 from the Ethernet source address
and compares it with the low 64 bits of the IPv6 source address.
The existing guard only rejects an invalid MAC header when
`par->fragoff != 0`. For packets with `par->fragoff == 0`, `eui64_mt6()`
can still reach `eth_hdr(skb)` even when the MAC header is not valid.
Fix this by removing the `par->fragoff != 0` condition so that packets
with an invalid MAC header are rejected before accessing `eth_hdr(skb)`.
CVSS Score
9.4
EPSS Score
0.001
Published
2026-04-25
In the Linux kernel, the following vulnerability has been resolved:
net/sched: sch_netem: fix out-of-bounds access in packet corruption
In netem_enqueue(), the packet corruption logic uses
get_random_u32_below(skb_headlen(skb)) to select an index for
modifying skb->data. When an AF_PACKET TX_RING sends fully non-linear
packets over an IPIP tunnel, skb_headlen(skb) evaluates to 0.
Passing 0 to get_random_u32_below() takes the variable-ceil slow path
which returns an unconstrained 32-bit random integer. Using this
unconstrained value as an offset into skb->data results in an
out-of-bounds memory access.
Fix this by verifying skb_headlen(skb) is non-zero before attempting
to corrupt the linear data area. Fully non-linear packets will silently
bypass the corruption logic.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-04-25