Linux: >> Linux Kernel >> 5.15.27 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
nfc: pn533: properly drop the usb interface reference on disconnect
When the device is disconnected from the driver, there is a "dangling"
reference count on the usb interface that was grabbed in the probe
callback. Fix this up by properly dropping the reference after we are
done with it.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
scsi: target: Fix recursive locking in __configfs_open_file()
In flush_write_buffer, &p->frag_sem is acquired and then the loaded store
function is called, which, here, is target_core_item_dbroot_store(). This
function called filp_open(), following which these functions were called
(in reverse order), according to the call trace:
down_read
__configfs_open_file
do_dentry_open
vfs_open
do_open
path_openat
do_filp_open
file_open_name
filp_open
target_core_item_dbroot_store
flush_write_buffer
configfs_write_iter
target_core_item_dbroot_store() tries to validate the new file path by
trying to open the file path provided to it; however, in this case, the bug
report shows:
db_root: not a directory: /sys/kernel/config/target/dbroot
indicating that the same configfs file was tried to be opened, on which it
is currently working on. Thus, it is trying to acquire frag_sem semaphore
of the same file of which it already holds the semaphore obtained in
flush_write_buffer(), leading to acquiring the semaphore in a nested manner
and a possibility of recursive locking.
Fix this by modifying target_core_item_dbroot_store() to use kern_path()
instead of filp_open() to avoid opening the file using filesystem-specific
function __configfs_open_file(), and further modifying it to make this fix
compatible.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
net: vxlan: fix nd_tbl NULL dereference when IPv6 is disabled
When booting with the 'ipv6.disable=1' parameter, the nd_tbl is never
initialized because inet6_init() exits before ndisc_init() is called
which initializes it. If an IPv6 packet is injected into the interface,
route_shortcircuit() is called and a NULL pointer dereference happens on
neigh_lookup().
BUG: kernel NULL pointer dereference, address: 0000000000000380
Oops: Oops: 0000 [#1] SMP NOPTI
[...]
RIP: 0010:neigh_lookup+0x20/0x270
[...]
Call Trace:
<TASK>
vxlan_xmit+0x638/0x1ef0 [vxlan]
dev_hard_start_xmit+0x9e/0x2e0
__dev_queue_xmit+0xbee/0x14e0
packet_sendmsg+0x116f/0x1930
__sys_sendto+0x1f5/0x200
__x64_sys_sendto+0x24/0x30
do_syscall_64+0x12f/0x1590
entry_SYSCALL_64_after_hwframe+0x76/0x7e
Fix this by adding an early check on route_shortcircuit() when protocol
is ETH_P_IPV6. Note that ipv6_mod_enabled() cannot be used here because
VXLAN can be built-in even when IPv6 is built as a module.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
atm: lec: fix null-ptr-deref in lec_arp_clear_vccs
syzkaller reported a null-ptr-deref in lec_arp_clear_vccs().
This issue can be easily reproduced using the syzkaller reproducer.
In the ATM LANE (LAN Emulation) module, the same atm_vcc can be shared by
multiple lec_arp_table entries (e.g., via entry->vcc or entry->recv_vcc).
When the underlying VCC is closed, lec_vcc_close() iterates over all
ARP entries and calls lec_arp_clear_vccs() for each matched entry.
For example, when lec_vcc_close() iterates through the hlists in
priv->lec_arp_empty_ones or other ARP tables:
1. In the first iteration, for the first matched ARP entry sharing the VCC,
lec_arp_clear_vccs() frees the associated vpriv (which is vcc->user_back)
and sets vcc->user_back to NULL.
2. In the second iteration, for the next matched ARP entry sharing the same
VCC, lec_arp_clear_vccs() is called again. It obtains a NULL vpriv from
vcc->user_back (via LEC_VCC_PRIV(vcc)) and then attempts to dereference it
via `vcc->pop = vpriv->old_pop`, leading to a null-ptr-deref crash.
Fix this by adding a null check for vpriv before dereferencing
it. If vpriv is already NULL, it means the VCC has been cleared
by a previous call, so we can safely skip the cleanup and just
clear the entry's vcc/recv_vcc pointers.
The entire cleanup block (including vcc_release_async()) is placed inside
the vpriv guard because a NULL vpriv indicates the VCC has already been
fully released by a prior iteration — repeating the teardown would
redundantly set flags and trigger callbacks on an already-closing socket.
The Fixes tag points to the initial commit because the entry->vcc path has
been vulnerable since the original code. The entry->recv_vcc path was later
added by commit 8d9f73c0ad2f ("atm: fix a memory leak of vcc->user_back")
with the same pattern, and both paths are fixed here.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
irqchip/sifive-plic: Fix frozen interrupt due to affinity setting
PLIC ignores interrupt completion message for disabled interrupt, explained
by the specification:
The PLIC signals it has completed executing an interrupt handler by
writing the interrupt ID it received from the claim to the
claim/complete register. The PLIC does not check whether the completion
ID is the same as the last claim ID for that target. If the completion
ID does not match an interrupt source that is currently enabled for
the target, the completion is silently ignored.
This caused problems in the past, because an interrupt can be disabled
while still being handled and plic_irq_eoi() had no effect. That was fixed
by checking if the interrupt is disabled, and if so enable it, before
sending the completion message. That check is done with irqd_irq_disabled().
However, that is not sufficient because the enable bit for the handling
hart can be zero despite irqd_irq_disabled(d) being false. This can happen
when affinity setting is changed while a hart is still handling the
interrupt.
This problem is easily reproducible by dumping a large file to uart (which
generates lots of interrupts) and at the same time keep changing the uart
interrupt's affinity setting. The uart port becomes frozen almost
instantaneously.
Fix this by checking PLIC's enable bit instead of irqd_irq_disabled().
CVSS Score
5.5
EPSS Score
0.001
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
IB/mthca: Add missed mthca_unmap_user_db() for mthca_create_srq()
Fix a user triggerable leak on the system call failure path.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
wifi: mac80211: fix NULL pointer dereference in mesh_rx_csa_frame()
In mesh_rx_csa_frame(), elems->mesh_chansw_params_ie is dereferenced
at lines 1638 and 1642 without a prior NULL check:
ifmsh->chsw_ttl = elems->mesh_chansw_params_ie->mesh_ttl;
...
pre_value = le16_to_cpu(elems->mesh_chansw_params_ie->mesh_pre_value);
The mesh_matches_local() check above only validates the Mesh ID,
Mesh Configuration, and Supported Rates IEs. It does not verify the
presence of the Mesh Channel Switch Parameters IE (element ID 118).
When a received CSA action frame omits that IE, ieee802_11_parse_elems()
leaves elems->mesh_chansw_params_ie as NULL, and the unconditional
dereference causes a kernel NULL pointer dereference.
A remote mesh peer with an established peer link (PLINK_ESTAB) can
trigger this by sending a crafted SPECTRUM_MGMT/CHL_SWITCH action frame
that includes a matching Mesh ID and Mesh Configuration IE but omits the
Mesh Channel Switch Parameters IE. No authentication beyond the default
open mesh peering is required.
Crash confirmed on kernel 6.17.0-5-generic via mac80211_hwsim:
BUG: kernel NULL pointer dereference, address: 0000000000000000
Oops: Oops: 0000 [#1] SMP NOPTI
RIP: 0010:ieee80211_mesh_rx_queued_mgmt+0x143/0x2a0 [mac80211]
CR2: 0000000000000000
Fix by adding a NULL check for mesh_chansw_params_ie after
mesh_matches_local() returns, consistent with how other optional IEs
are guarded throughout the mesh code.
The bug has been present since v3.13 (released 2014-01-19).
CVSS Score
5.5
EPSS Score
0.001
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
wifi: libertas: fix use-after-free in lbs_free_adapter()
The lbs_free_adapter() function uses timer_delete() (non-synchronous)
for both command_timer and tx_lockup_timer before the structure is
freed. This is incorrect because timer_delete() does not wait for
any running timer callback to complete.
If a timer callback is executing when lbs_free_adapter() is called,
the callback will access freed memory since lbs_cfg_free() frees the
containing structure immediately after lbs_free_adapter() returns.
Both timer callbacks (lbs_cmd_timeout_handler and lbs_tx_lockup_handler)
access priv->driver_lock, priv->cur_cmd, priv->dev, and other fields,
which would all be use-after-free violations.
Use timer_delete_sync() instead to ensure any running timer callback
has completed before returning.
This bug was introduced in commit 8f641d93c38a ("libertas: detect TX
lockups and reset hardware") where del_timer() was used instead of
del_timer_sync() in the cleanup path. The command_timer has had the
same issue since the driver was first written.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
netfilter: xt_IDLETIMER: reject rev0 reuse of ALARM timer labels
IDLETIMER revision 0 rules reuse existing timers by label and always call
mod_timer() on timer->timer.
If the label was created first by revision 1 with XT_IDLETIMER_ALARM,
the object uses alarm timer semantics and timer->timer is never initialized.
Reusing that object from revision 0 causes mod_timer() on an uninitialized
timer_list, triggering debugobjects warnings and possible panic when
panic_on_warn=1.
Fix this by rejecting revision 0 rule insertion when an existing timer with
the same label is of ALARM type.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-03-20
In the Linux kernel, the following vulnerability has been resolved:
net: add xmit recursion limit to tunnel xmit functions
Tunnel xmit functions (iptunnel_xmit, ip6tunnel_xmit) lack their own
recursion limit. When a bond device in broadcast mode has GRE tap
interfaces as slaves, and those GRE tunnels route back through the
bond, multicast/broadcast traffic triggers infinite recursion between
bond_xmit_broadcast() and ip_tunnel_xmit()/ip6_tnl_xmit(), causing
kernel stack overflow.
The existing XMIT_RECURSION_LIMIT (8) in the no-qdisc path is not
sufficient because tunnel recursion involves route lookups and full IP
output, consuming much more stack per level. Use a lower limit of 4
(IP_TUNNEL_RECURSION_LIMIT) to prevent overflow.
Add recursion detection using dev_xmit_recursion helpers directly in
iptunnel_xmit() and ip6tunnel_xmit() to cover all IPv4/IPv6 tunnel
paths including UDP encapsulated tunnels (VXLAN, Geneve, etc.).
Move dev_xmit_recursion helpers from net/core/dev.h to public header
include/linux/netdevice.h so they can be used by tunnel code.
BUG: KASAN: stack-out-of-bounds in blake2s.constprop.0+0xe7/0x160
Write of size 32 at addr ffff88810033fed0 by task kworker/0:1/11
Workqueue: mld mld_ifc_work
Call Trace:
<TASK>
__build_flow_key.constprop.0 (net/ipv4/route.c:515)
ip_rt_update_pmtu (net/ipv4/route.c:1073)
iptunnel_xmit (net/ipv4/ip_tunnel_core.c:84)
ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847)
gre_tap_xmit (net/ipv4/ip_gre.c:779)
dev_hard_start_xmit (net/core/dev.c:3887)
sch_direct_xmit (net/sched/sch_generic.c:347)
__dev_queue_xmit (net/core/dev.c:4802)
bond_dev_queue_xmit (drivers/net/bonding/bond_main.c:312)
bond_xmit_broadcast (drivers/net/bonding/bond_main.c:5279)
bond_start_xmit (drivers/net/bonding/bond_main.c:5530)
dev_hard_start_xmit (net/core/dev.c:3887)
__dev_queue_xmit (net/core/dev.c:4841)
ip_finish_output2 (net/ipv4/ip_output.c:237)
ip_output (net/ipv4/ip_output.c:438)
iptunnel_xmit (net/ipv4/ip_tunnel_core.c:86)
gre_tap_xmit (net/ipv4/ip_gre.c:779)
dev_hard_start_xmit (net/core/dev.c:3887)
sch_direct_xmit (net/sched/sch_generic.c:347)
__dev_queue_xmit (net/core/dev.c:4802)
bond_dev_queue_xmit (drivers/net/bonding/bond_main.c:312)
bond_xmit_broadcast (drivers/net/bonding/bond_main.c:5279)
bond_start_xmit (drivers/net/bonding/bond_main.c:5530)
dev_hard_start_xmit (net/core/dev.c:3887)
__dev_queue_xmit (net/core/dev.c:4841)
ip_finish_output2 (net/ipv4/ip_output.c:237)
ip_output (net/ipv4/ip_output.c:438)
iptunnel_xmit (net/ipv4/ip_tunnel_core.c:86)
ip_tunnel_xmit (net/ipv4/ip_tunnel.c:847)
gre_tap_xmit (net/ipv4/ip_gre.c:779)
dev_hard_start_xmit (net/core/dev.c:3887)
sch_direct_xmit (net/sched/sch_generic.c:347)
__dev_queue_xmit (net/core/dev.c:4802)
bond_dev_queue_xmit (drivers/net/bonding/bond_main.c:312)
bond_xmit_broadcast (drivers/net/bonding/bond_main.c:5279)
bond_start_xmit (drivers/net/bonding/bond_main.c:5530)
dev_hard_start_xmit (net/core/dev.c:3887)
__dev_queue_xmit (net/core/dev.c:4841)
mld_sendpack
mld_ifc_work
process_one_work
worker_thread
</TASK>
CVSS Score
5.5
EPSS Score
0.001
Published
2026-03-20