| CVE |
Vendors |
Products |
Updated |
CVSS v3.1 |
| In the Linux kernel, the following vulnerability has been resolved:
sched_ext: Fix CPU hotplug hang when a dying CPU's tasks sit in the BPF scheduler
A CPU going down has to empty its own rq. Its hotplug thread waits in
sched_cpu_wait_empty() until nothing else is left, and the only thing that
wakes it is balance_push(), which runs from __schedule() on the dying CPU
and pushes off the migratable tasks the CPU picks.
sched_ext breaks this. A task sitting on a user DSQ or held by the BPF
scheduler is still counted on its rq, but an inactive CPU no longer calls
ops.dispatch() and can't pull the task back. The dying CPU goes idle with
the task still counted, and one of two things happens:
- Another CPU consumes the task. The rq empties without a __schedule() on
the dying CPU, so the hotplug thread is never woken and cpu_down() hangs
holding cpu_hotplug_lock.
- The task is affine only to the dying CPU. Nothing can move it, and the
offline stalls until the watchdog ejects the BPF scheduler.
When the rq goes offline, re-enqueue every task on it that isn't already on
the local DSQ. An enqueue on an offline rq lands on the local DSQ, so the
dying CPU itself picks the tasks and balance_push() pushes them off, the
same as for the other sched classes. From then on no sched_ext path on
another CPU can pull a task off the rq.
ops.dispatch() currently stops as soon as the CPU goes inactive, and CPU
hotplug then waits for an RCU grace period before taking the rq offline. A
BPF-held task affine only to the dying CPU and preempted inside an RCU
read-side critical section would block that grace period, and the rq would
never go offline. Test SCX_RQ_ONLINE directly so that ops.dispatch() keeps
running until the rq goes offline. Only the dying CPU's own hotplug thread
clears the flag during teardown, and task_can_run_on_remote_rq() still keeps
other rqs' tasks off the CPU. |
| In the Linux kernel, the following vulnerability has been resolved:
readdir: take no inode lock on an immutable directory
iterate_dir() takes the directory's i_rwsem shared and holds it across
->iterate_shared(). For a directory that never has an entry and is
never removed the lock keeps nothing still, it only orders every reader
and every writer of that inode behind each other.
For the directory of a nullfs instance that matters. The instance of
the initial mount namespace is the root of every empty mount namespace
and the private instance is the root of every kernel thread, so one
inode is shared across users who have nothing else in common. And a
reader can hold the lock for as long as it likes: back the getdents()
buffer with a mapping of a file on a FUSE mount of your own, let the
copy of "." and ".." fault and let the server wait. Queue an exclusive
taker behind it, a mkdir() in that directory goes through start_dirop()
before the read-only mount is reported, and from then on every lookup
that misses the dcache in that directory, every create and every mount
on it waits until the server answers. One user of an empty mount
namespace stalls all the others.
Add FOP_IMMUTABLE for the file operations of a directory that never
changes and is never removed and let iterate_dir() skip the lock for
it. The flag never changes for a file, ->f_pos is protected by
f_pos_lock since directories are FMODE_ATOMIC_POS, IS_DEADDIR can't be
set on such a directory and neither touch_atime() nor fsnotify take
i_rwsem. Set it on the nullfs directory. The placeholder directories of
libfs never have an entry either but their owners remove them, so they
keep the lock. |
| In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix heap out-of-bounds write in krb5_authenticate()
In krb5_authenticate(), out_len is calculated to determine available
headroom in response_buf for the incoming Kerberos AP-REP token. However,
when SMB2_SESSION_SETUP is processed as a non-first element of a compounded
SMB2 request, the calculation omits work->next_smb2_rsp_hdr_off.
This causes out_len to overstate remaining buffer headroom by
the cumulative size of prior responses in the compound chain. Consequently,
the length check in ksmbd_krb5_authenticate()
(*out_len <= resp->spnego_blob_len) passes erroneously, allowing memcpy()
to write the AP-REP blob past the end of response_buf into adjacent kernel
heap memory.
Fix this by subtracting work->next_smb2_rsp_hdr_off when computing out_len,
ensuring it accurately reflects physical remaining buffer space. |
| In the Linux kernel, the following vulnerability has been resolved:
KVM: x86: Use active memslots for the per-vCPU MMIO cache
KVM tags the per-vCPU MMIO cache with a memslot generation so that a
memslot update invalidates cached MMIO information. Both the fill and
validation paths use kvm_memslots(), which unconditionally selects address
space 0, even when the vCPU is running in SMM and using address space 1.
Commit 56f17dd3fbc4 ("kvm: x86: fix stale mmio cache bug") added the
memslot generation to the cache key so that a memslot update could not
leave a stale entry valid. When commit 699023e23965 ("KVM: x86: add SMM
to the MMU role, support SMRAM address space") added the SMM address space,
these helpers were not converted to use the active memslots.
Consequently, an update to the SMM memslots can leave an entry from the old
SMM address space apparently valid after the vCPU returns to the normal
address space. A guest can then cause an access to valid RAM at the same
GFN to be returned to userspace as KVM_EXIT_MMIO.
Completing that exit through the VMM's RAM address space writes the backing
page without going through KVM's write-tracking path. If the page backs a
nested EPT table, KVM can continue using shadow translations derived from
the old contents. The WARN_ON_ONCE() in kvm_mmu_write_protect_fault()
catches this invalid cache and memslot combination.
Use the vCPU's active memslots when caching and validating the entry.
Memslot generations are unique across address spaces, so the generation
also distinguishes the normal and SMM views. This matches the MMIO SPTE
cache, which already uses kvm_vcpu_memslots().
On an unpatched current-mainline kernel, a regression test that fills the
cache in SMM and updates only the SMM memslots fails the intended RAM write
and triggers the kvm_mmu_write_protect_fault() warning. With this change,
the same test completes the RAM write without a warning. The x86/smm_test,
set_memory_region_test, and memslot_modification_stress_test selftests also
pass. |
| In the Linux kernel, the following vulnerability has been resolved:
bnxt_en: fix DMA mapping length for padded small packets
Stefan Fleischmann reported Intel IOMMU DMA Read faults on BCM57412
NetXtreme-E NICs when transmitting packets on VLAN/macvlan interfaces:
DMAR: [DMA Read NO_PASID] Request device [18:00.0] fault addr 0xfc499000
[fault reason 0x06] PTE Read access is not set
bnxt_en 0000:18:00.0 eno1np0: Abandoning msg {0xb4 0x41a} len: 0 due to firmware status: 0x2000001
...
NETDEV WATCHDOG: eno1np0 (bnxt_en): transmit queue 0 timed out
The fault address (0xfc499000) is on an exact 4KB page boundary,
pointing to a DMA read buffer overrun.
In bnxt_start_xmit(), packets smaller than BNXT_MIN_PKT_SIZE (52 bytes),
such as 42-byte untagged ARP frames, are padded:
if (length < BNXT_MIN_PKT_SIZE) {
pad = BNXT_MIN_PKT_SIZE - length;
if (skb_pad(skb, pad))
goto tx_kick_pending;
length = BNXT_MIN_PKT_SIZE;
}
mapping = dma_map_single(&pdev->dev, skb->data, len, DMA_TO_DEVICE);
...
dma_unmap_len_set(tx_buf, len, len);
However, 'len' was initialized earlier to skb_headlen(skb) (e.g. 42 bytes)
and is left unadjusted after padding. Consequently, dma_map_single() and
dma_unmap_len_set() map and track only 42 bytes.
Later, the hardware TX buffer descriptor is programmed with the padded length:
txbd->tx_bd_len_flags_type =
cpu_to_le32(((len + pad) << TX_BD_LEN_SHIFT) | flags |
TX_BD_FLAGS_PACKET_END);
The NIC DMA engine is thus instructed to read 52 bytes from a region where
only 42 bytes were DMA-mapped. If skb->data ends near the boundary of a 4KB
page (within 'pad' bytes of the next page), the hardware DMA read overruns
into the unmapped adjacent page, triggering an IOMMU fault.
This issue was exposed after commit 447cbe95ebb9 ("vlan: fix skb_under_panic
and races when toggling HW VLAN offload") because reserving extra VLAN
headroom rounded LL_RESERVED_SPACE from 48 up to 64 bytes, shifting skb->data
offsets and potentially causing small frames to land right against page
boundaries.
Fix this by using skb_put_padto(skb, BNXT_MIN_PKT_SIZE) in
bnxt_start_xmit(), before skb_shinfo(skb)->nr_frags is sampled,
because padding might linearize the skb.
This ensures skb->len and skb_headlen(skb) reflect the padded size so
that dma_map_single() maps the full buffer and the descriptor length is
consistent. This also removes the temporary 'pad' variable and masking logic.
The padding is done after the SW USO branch, otherwise
bnxt_sw_udp_gso_xmit() would account the padding as UDP payload
and send it in extra segments.
Note that SW USO segments are still not padded: with IPv4, a segment
carrying less than 10 bytes of UDP payload (small gso_size, or a short
last segment) is sent as a frame shorter than BNXT_MIN_PKT_SIZE.
This is a separate issue, left for a followup patch. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: udp: Create exceptions before socket matching
Currently, when ICMPv6 Packet Too Big and Redirect Message packets are
locally delivered and quote a UDP packet, an exception is only created
in the IPv6 exception cache if the kernel can match the UDP packet to an
existing socket.
This behavior allows off-path attackers to conduct a side-channel attack
on the exception cache in order to discover the ephemeral port used by a
connected UDP socket.
Commit 4785305c05b2 ("ipv6: use siphash in rt6_exception_hash()") and
commit a00df2caffed ("ipv6: make exception cache less predictible") tried
to mitigate such attacks by making it harder for attackers to discover
hash collisions in the exception cache and by randomizing the number of
exceptions a hash bucket can hold, respectively. Unfortunately, both of
the mitigations can be bypassed.
Instead, mitigate such attacks by always creating an exception, even
before trying to find a matching socket. Do that by calling
ip6_update_pmtu() and ip6_redirect(), the helpers used when the quoted
packet did not originate from a socket.
This means that guesses (right or wrong) from an off-path attacker will
always result in an exception being created or updated in the cache that
the attacker can observe.
Pass the ifindex of the ingress device and the default uid, in a similar
fashion to icmpv6_err(). Unlike IPv4, an oif of 0 would not match any
nexthop in ip6_redirect_nh_match() and no exception would be created in
response to a Redirect Message.
Note that this does not allow attackers to create exceptions that they
could not create before, as both helpers can already be reached with
little to no validation. For example, by sending an ICMPv6 error that
quotes an ICMPv6 Echo Reply or one that quotes a UDP source port that
matches a wildcard socket.
Also note that in the good case (matched socket) the above scheme comes
at the cost of an extra route lookup, as the no socket helpers perform
their own lookup before the one performed by ip6_sk_update_pmtu() /
ip6_sk_redirect(). When the two resolve to different nexthops, it also
results in two exceptions being created for the same destination IP. One
in the exception cache of the nexthop resolved by the no socket helpers
and another in the exception cache of the nexthop used by the socket. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv4: stop PMTU walk when nexthop group shrinks
Commit 7d3f3b4367f3 ("net: ipv4: Cache pmtu for all packet paths if
multipath enabled") made __ip_rt_update_pmtu() update every path.
For nexthop objects, fib_info_num_path() and fib_info_nhc()
independently load nh->nh_grp. RCU protects each group's lifetime but
does not make the loads observe the same group. If replacement shrinks
the group after the loop accepts an index, fib_info_nhc() returns NULL
and update_or_create_fnhe() dereferences it.
A deterministic probe only widened the existing window between the real
operations. On v7.2, an RTM_NEWNEXTHOP replacement published a
one-member group after the PMTU reader accepted index 1 from a two-member
group, producing:
KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007]
RIP: update_or_create_fnhe+0x45/0x15b0
Stop when the indexed path is absent. Groups are dense, so no later
index exists in that snapshot. The same real-writer window completed
114,423 PMTU iterations without an oops with this check. A reproducer
is available on request.
Replacement requires CAP_NET_ADMIN in the network namespace. Where
unprivileged user namespaces are permitted, a local user can obtain it
in a new user and network namespace. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv4: stop exception dump when nexthop group shrinks
Commit 4ce5dc9316de ("inet: switch inet_dump_fib() to RCU
protection") allowed IPv4 FIB dumps to run concurrently with nexthop
replacement.
fib_dump_info_fnhe() uses fib_info_num_path() as the loop bound,
then fib_info_nhc() independently reloads nh->nh_grp. If
RTM_NEWNEXTHOP replaces a group with fewer paths between those loads,
fib_info_nhc() returns NULL and the dump dereferences it through
nhc_flags.
Stop the walk when the indexed path is absent. Nexthop groups are
dense, so the current snapshot has no later path. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv4: stop route notification sizing when nexthop group shrinks
Commit 680aea08e78c ("net: ipv4: Emit notification when fib
hardware flags are changed") added an RCU-only fib_nlmsg_size() call
for asynchronous hardware flag notifications.
fib_nlmsg_size() checks fib_info_num_path() before each iteration,
then fib_info_nhc() independently reloads nh->nh_grp. If
RTM_NEWNEXTHOP replaces a group with fewer paths between those loads,
fib_info_nhc() returns NULL and fib_nexthop_nlmsg_size() dereferences
it.
Stop sizing when the indexed path is absent. Nexthop groups are
dense, so the current snapshot has no later path. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv4: do not warn on route notification size race
Commit 680aea08e78c ("net: ipv4: Emit notification when fib hardware
flags are changed") added asynchronous route notifications for hardware
flag changes.
fib_alias_hw_flags_set() sizes the skb with fib_nlmsg_size() and later
fills it with fib_dump_info() while holding only RCU. With nexthop
compatibility mode enabled, a concurrent replacement can grow the group
between these independent snapshots. fib_dump_info() can then
legitimately return -EMSGSIZE, so the warning does not prove a sizing bug.
Remove the warning. The existing error path still frees the skb and
reports the error to listeners. |
| In the Linux kernel, the following vulnerability has been resolved:
ipv6: do not warn on route notification size race
fib6_info_hw_flags_set() sizes the skb with rt6_nlmsg_size() and later
fills it with rt6_fill_node(). With nexthop compatibility mode enabled,
a concurrent replacement can grow the group between these independent
snapshots. rt6_fill_node() can then legitimately return -EMSGSIZE, so
the warning does not prove a sizing bug.
Remove the warning. The existing error path still frees the skb and
reports the error to listeners. |
| In the Linux kernel, the following vulnerability has been resolved:
ALSA: ctxfi: Fix memory leakage when clearing DAO input mappers
Commit e576e7843c0d ("ALSA: ctxfi: Simplify dao_clear_{left,right}_input() functions")
centralized the DAO input mapper clearing logic in
dao_clear_input(), but omitted the kfree() calls.
It removes the mapper entries from the list and sets their pointers
to NULL without freeing the allocated array. This leaks memory each
time dao_clear_input() is called.
Store the base pointer of the allocation before clearing the mapper
entries and free the array after removing entries from the list. |
| In the Linux kernel, the following vulnerability has been resolved:
dm ioctl: don't let data_start run past the buffer
struct dm_ioctl has seven bytes of trailing padding, so the smallest
buffer userspace is allowed to ask for, offsetof(struct dm_ioctl, data),
is seven bytes shorter than sizeof(struct dm_ioctl).
get_result_buffer() sets data_start to sizeof(struct dm_ioctl) without
looking at how big the buffer actually is. Ask for the minimum and
data_start ends up seven bytes past the end. Callers add it to
data_size, and ctl_ioctl() copies that much back to userspace:
BUG: KASAN: slab-out-of-bounds in _copy_to_user+0xad/0xd0
Read of size 312 at addr ffff8880169e4c00 by task repro-dm/140
ctl_ioctl+0x5e3/0xcb0
dm_ctl_ioctl+0x25/0x40
allocated 305-byte region [ffff8880169e4c00, ffff8880169e4d31)
A DM_LIST_DEVICES with data_size set to 305 is enough to hit it, and the
seven bytes that leak are whatever sat next to the allocation.
Clamp data_start to the buffer size.
Note that this is not a security bug because the out-of-bounds read can
only be triggered by root. |
| In the Linux kernel, the following vulnerability has been resolved:
xen/netfront: don't leak the skb when xennet_fill_frags() fails
When a response chain has more slots than fit in the skb's frags,
xennet_fill_frags() returns an error and xennet_poll() jumps to its
error path. That path moves what's left on tmpq to errq to be freed,
but the skb being filled was already dequeued from tmpq, so it's never
freed. Each chain that overflows leaks the skb and the pages attached
to it as frags, and the backend decides how many slots it sends.
Put the skb back on tmpq before taking the error path, like the
xennet_set_skb_gso() failure just above it does. |
| In the Linux kernel, the following vulnerability has been resolved:
tcp: reject net_iov in zerocopy receive mapping hints
After copying a readable prefix, receive_fallback_to_copy() asks
tcp_zerocopy_set_hint_for_skb() where page mapping can resume. If the
next skb is unreadable, find_next_mappable_frag() passes its net_iov
fragment to can_map_frag().
skb_frag_page() returns NULL for a net_iov, but can_map_frag()
dereferences it in PageCompound(). A v7.2 KASAN run on a connected TCP
socket with 64 readable bytes followed by a 4096-byte NET_IOV_DMABUF
fragment reported:
BUG: KASAN: null-ptr-deref in can_map_frag
tcp_zerocopy_receive -> can_map_frag
Kernel panic - not syncing: KASAN: panic_on_warn set
The diagnostic inserted the net_iov directly because the test host has
no devmem-capable NIC. Hardware end-to-end reachability remains untested
and requires CONFIG_NET_DEVMEM plus a supported DMA-buf-bound RX queue.
Reject all net_iov fragments before skb_frag_page(). This covers both
DMABUF and IOURING net_iov types while leaving page-backed checks
unchanged. With the guard, the same queue copied the readable prefix,
returned a 4096-byte skip hint, and completed without a fault. |
| In the Linux kernel, the following vulnerability has been resolved:
tipc: destroy topsrv workqueues before closing connections
tipc_topsrv_stop() closed subscriber connections while the topology
server's send and receive workqueues were still running. Socket
callbacks and subscription events could then queue more work, and
in-flight send/recv work could drop the last connection reference
during the conn_idr walk.
That race produced several teardown failures: refcount_t addition on
0 from conn_get() on a connection whose release was blocked on
idr_lock, a subsequent use-after-free in tipc_conn_close(),
queue_work() on an already destroyed workqueue from the listener
data-ready callback, and an RCU stall in tipc_topsrv_exit_net()
while the walk spun under idr_lock.
Clear srv->listener under idr_lock so it acts as a shutdown flag,
skip queue_work() once it is NULL, destroy the workqueues to flush
in-flight work, and only then close the remaining connections.
Refuse tipc_conn_lookup() after that flag is cleared, and drop
idr_lock when the teardown walk finds no connection, so an
in-flight subscription event cannot pin idr_in_use while the
walk holds the lock.
v3 supersedes the narrower in-thread diff Tung Quang Nguyen
posted on 2026-09-23. It keeps his teardown order and adds the
lookup refusal and the empty-idr unlock. |
| In the Linux kernel, the following vulnerability has been resolved:
tipc: hold a reference to nodes found by link name
tipc_node_find_by_name() returns a node after dropping its RCU read lock
without taking a reference. The LINK_SET, LINK_GET and LINK_RESET_STATS
handlers then lock and access the node, racing with timer-driven cleanup of
a down peer. Generic netlink serialization does not exclude the node
timer.
The following interleaving can leave a handler using a freed node:
CPU 0: find the node under RCU and release the node read lock
CPU 1: tipc_node_timeout() clears the links and unlinks the down node
CPU 1: drop the list and timer references, queuing tipc_node_free()
CPU 0: leave the RCU read-side critical section
CPU 1: complete the grace period and free the node
CPU 0: acquire the node lock through the stale pointer
LINK_SET also uses the node's media address after releasing the node lock,
when passing queued packets to tipc_bearer_xmit().
KASAN on v7.3-rc5 reported:
BUG: KASAN: slab-use-after-free in _raw_read_lock_bh
Write of size 4 at addr ffff88807e06f008 by task poc/92
Call Trace:
_raw_read_lock_bh kernel/locking/spinlock.c:287
tipc_nl_node_set_link net/tipc/node.c:2475
genl_family_rcv_msg_doit net/netlink/genetlink.c:1114
genl_rcv_msg net/netlink/genetlink.c:1209
netlink_rcv_skb net/netlink/af_netlink.c:2575
Allocated by task 0:
tipc_node_create net/tipc/node.c:539
tipc_node_check_dest net/tipc/node.c:1196
tipc_disc_rcv net/tipc/discover.c:252
Freed by task 92:
kfree mm/slub.c:6801
rcu_core kernel/rcu/tree.c:2919
Last potentially related work creation:
__call_rcu_common.constprop.0 kernel/rcu/tree.c:3181
tipc_node_timeout net/tipc/node.c:814
Acquire a reference to the selected node with kref_get_unless_zero() before
leaving RCU, returning NULL if the node has already been released. Release
that reference on every caller exit after the last node access, including
transmission in LINK_SET. Keep the existing link lookup order and locking
so concurrent link removal still takes the existing error paths. |
| In the Linux kernel, the following vulnerability has been resolved:
gpio: xilinx: fix runtime PM leak on request error path
pm_runtime_get_sync() leaves the usage counter incremented even when it
fails, and xgpio_request() returns the error without dropping it.
gpiolib does not call ->free() when ->request() fails, so xgpio_free(),
which holds the only matching pm_runtime_put(), never runs. The reference
is leaked and the controller can no longer runtime-suspend, so its clock
stays enabled.
Switch to pm_runtime_resume_and_get(), which only increments the usage
counter on success. |
| In the Linux kernel, the following vulnerability has been resolved:
ibmveth: h_free logical LAN on open-fail after register
ibmveth_open() registers the logical LAN, then allocates the RX
buffer pools. A pool failure jumps to out_free_buffer_pools without
h_free_logical_lan(), so PHYP still owns the buffer-list page when
it is unmapped. request_irq() failure already issued the hypercall
before taking the same label.
Move that h_free to the shared post-register unwind so both paths
deregister before the buffer list is unmapped. |
| In the Linux kernel, the following vulnerability has been resolved:
ice: fix metadata_dst refcount handling on representor teardown
ice_eswitch_release_repr() uses metadata_dst_free() to release the
representor's metadata_dst. metadata_dst_free() directly frees the
underlying memory without checking the dst_entry refcount.
When ice_eswitch_port_start_xmit() processes a packet, it takes a
reference via dst_hold() and attaches the metadata_dst to the skb.
If the representor is torn down while packets are still queued on
the lower device (e.g. in a qdisc), the metadata_dst is freed while
references are still held.
Use dst_release() instead, which correctly decrements the refcount
and only frees the object when all references are dropped. The dst
subsystem already handles metadata_dst cleanup in dst_destroy() when
DST_METADATA is set.
Other drivers sharing this pattern (nfp, airoha, bnxt) already use
dst_release() for their metadata_dst lifecycle. |
