Linux: >> Linux Kernel >> 6.12.27 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
bpf: return VMA snapshot from task_vma iterator
Holding the per-VMA lock across the BPF program body creates a lock
ordering problem when helpers acquire locks that depend on mmap_lock:
vm_lock -> i_rwsem -> mmap_lock -> vm_lock
Snapshot the VMA under the per-VMA lock in _next() via memcpy(), then
drop the lock before returning. The BPF program accesses only the
snapshot.
The verifier only trusts vm_mm and vm_file pointers (see
BTF_TYPE_SAFE_TRUSTED_OR_NULL in verifier.c). vm_file is reference-
counted with get_file() under the lock and released via fput() on the
next iteration or in _destroy(). vm_mm is already correct because
lock_vma_under_rcu() verifies vma->vm_mm == mm. All other pointers
are left as-is by memcpy() since the verifier treats them as untrusted.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
bpf: fix mm lifecycle in open-coded task_vma iterator
The open-coded task_vma iterator reads task->mm locklessly and acquires
mmap_read_trylock() but never calls mmget(). If the task exits
concurrently, the mm_struct can be freed as it is not
SLAB_TYPESAFE_BY_RCU, resulting in a use-after-free.
Safely read task->mm with a trylock on alloc_lock and acquire an mm
reference. Drop the reference via bpf_iter_mmput_async() in _destroy()
and error paths. bpf_iter_mmput_async() is a local wrapper around
mmput_async() with a fallback to mmput() on !CONFIG_MMU.
Reject irqs-disabled contexts (including NMI) up front. Operations used
by _next() and _destroy() (mmap_read_unlock, bpf_iter_mmput_async)
take spinlocks with IRQs disabled (pool->lock, pi_lock). Running from
NMI or from a tracepoint that fires with those locks held could
deadlock.
A trylock on alloc_lock is used instead of the blocking task_lock()
(get_task_mm) to avoid a deadlock when a softirq BPF program iterates
a task that already holds its alloc_lock on the same CPU.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
net: bcmgenet: fix racing timeout handler
The bcmgenet_timeout handler tries to take down all tx queues when
a single queue times out. This is over zealous and causes many race
conditions with queues that are still chugging along. Instead lets
only restart the timed out queue.
CVSS Score
9.8
EPSS Score
0.003
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
net: bcmgenet: fix off-by-one in bcmgenet_put_txcb
The write_ptr points to the next open tx_cb. We want to return the
tx_cb that gets rewinded, so we must rewind the pointer first then
return the tx_cb that it points to. That way the txcb can be correctly
cleaned up.
CVSS Score
9.8
EPSS Score
0.004
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: fix locking in hci_conn_request_evt() with HCI_PROTO_DEFER
When protocol sets HCI_PROTO_DEFER, hci_conn_request_evt() calls
hci_connect_cfm(conn) without hdev->lock. Generally hci_connect_cfm()
assumes it is held, and if conn is deleted concurrently -> UAF.
Only SCO and ISO set HCI_PROTO_DEFER and only for defer setup listen,
and HCI_EV_CONN_REQUEST is not generated for ISO. In the non-deferred
listening socket code paths, hci_connect_cfm(conn) is called with
hdev->lock held.
Fix by holding the lock.
CVSS Score
8.8
EPSS Score
0.002
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: hci_ldisc: Clear HCI_UART_PROTO_INIT on error
When hci_register_dev() fails in hci_uart_register_dev()
HCI_UART_PROTO_INIT is not cleared before calling hu->proto->close(hu)
and setting hu->hdev to NULL. This means incoming UART data will reach
the protocol-specific recv handler in hci_uart_tty_receive() after
resources are freed.
Clear HCI_UART_PROTO_INIT with a write lock before calling
hu->proto->close() and setting hu->hdev to NULL. The write lock ensures
all active readers have completed and no new reader can enter the
protocol recv path before resources are freed.
This allows the protocol-specific recv functions to remove the
"HCI_UART_REGISTERED" guard without risking a null pointer dereference
if hci_register_dev() fails.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
bpf: reject short IPv4/IPv6 inputs in bpf_prog_test_run_skb
bpf_prog_test_run_skb() calls eth_type_trans() first and then uses
skb->protocol to initialize sk family and address fields for the test
run.
For IPv4 and IPv6 packets, it may access ip_hdr(skb) or ipv6_hdr(skb)
even when the provided test input only contains an Ethernet header.
Reject the input earlier if the Ethernet frame carries IPv4/IPv6
EtherType but the L3 header is too short.
Fold the IPv4/IPv6 header length checks into the existing protocol
switch and return -EINVAL before accessing the network headers.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
ppp: require CAP_NET_ADMIN in target netns for unattached ioctls
/dev/ppp open is currently authorized against file->f_cred->user_ns,
while unattached administrative ioctls operate on current->nsproxy->net_ns.
As a result, a local unprivileged user can create a new user namespace
with CLONE_NEWUSER, gain CAP_NET_ADMIN only in that new user namespace,
and still issue PPPIOCNEWUNIT, PPPIOCATTACH, or PPPIOCATTCHAN against
an inherited network namespace.
Require CAP_NET_ADMIN in the user namespace that owns the target network
namespace before handling unattached PPP administrative ioctls.
This preserves normal pppd operation in the network namespace it is
actually privileged in, while rejecting the userns-only inherited-netns
case.
CVSS Score
8.8
EPSS Score
0.003
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix OOB in pcpu_init_value
An out-of-bounds read occurs when copying element from a
BPF_MAP_TYPE_CGROUP_STORAGE map to another pcpu map with the
same value_size that is not rounded up to 8 bytes.
The issue happens when:
1. A CGROUP_STORAGE map is created with value_size not aligned to
8 bytes (e.g., 4 bytes)
2. A pcpu map is created with the same value_size (e.g., 4 bytes)
3. Update element in 2 with data in 1
pcpu_init_value assumes that all sources are rounded up to 8 bytes,
and invokes copy_map_value_long to make a data copy, However, the
assumption doesn't stand since there are some cases where the source
may not be rounded up to 8 bytes, e.g., CGROUP_STORAGE, skb->data.
the verifier verifies exactly the size that the source claims, not
the size rounded up to 8 bytes by kernel, an OOB happens when the
source has only 4 bytes while the copy size(4) is rounded up to 8.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
net/rds: Restrict use of RDS/IB to the initial network namespace
Prevent using RDS/IB in network namespaces other than the initial one.
The existing RDS/IB code will not work properly in non-initial network
namespaces.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-24