Linux: >> Linux Kernel >> 6.18.11 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix double free in create_space_info() error path
When kobject_init_and_add() fails, the call chain is:
create_space_info()
-> btrfs_sysfs_add_space_info_type()
-> kobject_init_and_add()
-> failure
-> kobject_put(&space_info->kobj)
-> space_info_release()
-> kfree(space_info)
Then control returns to create_space_info():
btrfs_sysfs_add_space_info_type() returns error
-> goto out_free
-> kfree(space_info)
This causes a double free.
Keep the direct kfree(space_info) for the earlier failure path, but
after btrfs_sysfs_add_space_info_type() has called kobject_put(), let
the kobject release callback handle the cleanup.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
dm-verity-fec: fix reading parity bytes split across blocks (take 3)
fec_decode_bufs() assumes that the parity bytes of the first RS codeword
it decodes are never split across parity blocks.
This assumption is false. Consider v->fec->block_size == 4096 &&
v->fec->roots == 17 && fio->nbufs == 1, for example. In that case, each
call to fec_decode_bufs() consumes v->fec->roots * (fio->nbufs <<
DM_VERITY_FEC_BUF_RS_BITS) = 272 parity bytes.
Considering that the parity data for each message block starts on a
block boundary, the byte alignment in the parity data will iterate
through 272*i mod 4096 until the 3 parity blocks have been consumed. On
the 16th call (i=15), the alignment will be 4080 bytes into the first
block. Only 16 bytes remain in that block, but 17 parity bytes will be
needed. The code reads out-of-bounds from the parity block buffer.
Fortunately this doesn't normally happen, since it can occur only for
certain non-default values of fec_roots *and* when the maximum number of
buffers couldn't be allocated due to low memory. For example with
block_size=4096 only the following cases are affected:
fec_roots=17: nbufs in [1, 3, 5, 15]
fec_roots=19: nbufs in [1, 229]
fec_roots=21: nbufs in [1, 3, 5, 13, 15, 39, 65, 195]
fec_roots=23: nbufs in [1, 89]
Regardless, fix it by refactoring how the parity blocks are read.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
KVM: x86: check for nEPT/nNPT in slow flush hypercalls
Checking is_guest_mode(vcpu) is incorrect, because translate_nested_gpa()
is only valid if an L2 guest is running *with nested EPT/NPT enabled*.
Instead use the same condition as translate_nested_gpa() itself.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
net: rtnetlink: zero ifla_vf_broadcast to avoid stack infoleak in rtnl_fill_vfinfo
rtnl_fill_vfinfo() declares struct ifla_vf_broadcast on the stack
without initialisation:
struct ifla_vf_broadcast vf_broadcast;
The struct contains a single fixed 32-byte field:
/* include/uapi/linux/if_link.h */
struct ifla_vf_broadcast {
__u8 broadcast[32];
};
The function then copies dev->broadcast into it using dev->addr_len
as the length:
memcpy(vf_broadcast.broadcast, dev->broadcast, dev->addr_len);
On Ethernet devices (the overwhelming majority of SR-IOV NICs)
dev->addr_len is 6, so only the first 6 bytes of broadcast[] are
written. The remaining 26 bytes retain whatever was previously on
the kernel stack. The full struct is then handed to userspace via:
nla_put(skb, IFLA_VF_BROADCAST,
sizeof(vf_broadcast), &vf_broadcast)
leaking up to 26 bytes of uninitialised kernel stack per VF per
RTM_GETLINK request, repeatable.
The other vf_* structs in the same function are explicitly zeroed
for exactly this reason - see the memset() calls for ivi,
vf_vlan_info, node_guid and port_guid a few lines above.
vf_broadcast was simply missed when it was added.
Reachability: any unprivileged local process can open AF_NETLINK /
NETLINK_ROUTE without capabilities and send RTM_GETLINK with an
IFLA_EXT_MASK attribute carrying RTEXT_FILTER_VF. The kernel walks
each VF and emits IFLA_VF_BROADCAST, leaking 26 bytes of stack per
VF per request. Stack residue at this call site can include return
addresses and transient sensitive data; KASAN with stack
instrumentation, or KMSAN, will flag the nla_put() when reproduced.
Zero the on-stack struct before the partial memcpy, matching the
existing pattern used for the other vf_* structs in the same
function.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
RDMA/rxe: Reject unknown opcodes before ICRC processing
Even after applying commit 7244491dab34 ("RDMA/rxe: Validate pad and ICRC
before payload_size() in rxe_rcv"), a single unauthenticated UDP packet
can still trigger panic. That patch handled payload_size() underflow only
for valid opcodes with short packets, not for packets carrying an unknown
opcode. The unknown-opcode OOB read described below predates that commit
and reaches back to the initial Soft RoCE driver.
The check added there reads
pkt->paylen < header_size(pkt) + bth_pad(pkt) + RXE_ICRC_SIZE
where header_size(pkt) expands to rxe_opcode[pkt->opcode].length. The
rxe_opcode[] array has 256 entries but is only populated for defined IB
opcodes; any other entry (for example opcode 0xff) is zero-initialized, so
length == 0 and the check degenerates to
pkt->paylen < 0 + bth_pad(pkt) + RXE_ICRC_SIZE
which does not constrain pkt->paylen enough. rxe_icrc_hdr() then computes
rxe_opcode[pkt->opcode].length - RXE_BTH_BYTES
which underflows when length == 0 and passes a huge value to rxe_crc32(),
causing an out-of-bounds read of the skb payload.
Reproduced on v7.0-rc7 with that fix applied, QEMU/KVM with
CONFIG_RDMA_RXE=y and CONFIG_KASAN=y, after
rdma link add rxe0 type rxe netdev eth0
A single 48-byte UDP packet to port 4791 with BTH opcode=0xff and
QPN=IB_MULTICAST_QPN triggers:
BUG: KASAN: slab-out-of-bounds in crc32_le+0x115/0x170
Read of size 1 at addr ...
The buggy address is located 0 bytes to the right of
allocated 704-byte region
Call Trace:
crc32_le+0x115/0x170
rxe_icrc_hdr.isra.0+0x226/0x300
rxe_icrc_check+0x13f/0x3a0
rxe_rcv+0x6e1/0x16e0
rxe_udp_encap_recv+0x20a/0x320
udp_queue_rcv_one_skb+0x7ed/0x12c0
Subsequent packets with the same shape fault on unmapped memory and panic
the kernel. The trigger requires only module load and "rdma link add"; no
QP, no connection, and no authentication.
Fix this by rejecting packets whose opcode has no rxe_opcode[] entry,
detected via the zero mask or zero length, before any length arithmetic
runs.
CVSS Score
7.5
EPSS Score
0.006
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
platform/chrome: cros_ec_typec: Init mutex in Thunderbolt registration
cros_typec_register_thunderbolt() missed initializing the `adata->lock`
mutex. This leads to a NULL dereference when the mutex is later
acquired (e.g. in cros_typec_altmode_work()).
Initialize the mutex in cros_typec_register_thunderbolt() to fix the
issue.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
libceph: Fix slab-out-of-bounds access in auth message processing
If a (potentially corrupted) message of type CEPH_MSG_AUTH_REPLY
contains a positive value in its result field, it is treated as an
error code by ceph_handle_auth_reply() and returned to
handle_auth_reply(). Thereafter, an attempt is made to send the
preallocated message of type CEPH_MSG_AUTH, where the returned value is
interpreted as the size of the front segment to send. If the result
value in the message is greater than the size of the memory buffer
allocated for the front segment, an out-of-bounds access occurs, and
the content of the memory region beyond this buffer is sent out.
This patch fixes the issue by treating only negative values in the
result field as errors. Positive values are therefore treated as success
in the same way as a zero value. Additionally, a BUG_ON is added to
__send_prepared_auth_request() comparing the len parameter to
front_alloc_len to prevent sending the message if it exceeds the bounds
of the allocation and to make it easier to catch any logic flaws leading
to this.
CVSS Score
9.1
EPSS Score
0.005
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
ip6_gre: Use cached t->net in ip6erspan_changelink().
After commit 5e72ce3e3980 ("net: ipv6: Use link netns in newlink() of
rtnl_link_ops"), ip6erspan_newlink() correctly resolves the per-netns
ip6gre hash via link_net. ip6erspan_changelink() was not converted in
that series and still uses dev_net(dev), which diverges from the
device's creation netns after IFLA_NET_NS_FD migration.
This re-inserts the tunnel into the wrong per-netns hash. The
original netns keeps a stale entry. When that netns is later
destroyed, ip6gre_exit_rtnl_net() walks the stale entry, producing a
slab-use-after-free reported by KASAN, followed by a kernel BUG at
net/core/dev.c (LIST_POISON1) in unregister_netdevice_many_notify().
Reachable from an unprivileged user namespace (unshare --user
--map-root-user --net).
ip6gre_changelink() earlier in the same file already uses the cached
t->net; only ip6erspan_changelink() has the wrong shape.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
mm/damon/sysfs-schemes: protect memcg_path kfree() with damon_sysfs_lock
Patch series "mm/damon/sysfs-schemes: fix use-after-free for [memcg_]path".
Reads of 'memcg_path' and 'path' files in DAMON sysfs interface could race
with their writes, results in use-after-free. Fix those.
This patch (of 2):
damon_sysfs_scheme_filter->mmecg_path can be read and written by users,
via DAMON sysfs memcg_path file. It can also be indirectly read, for the
parameters {on,off}line committing to DAMON. The reads for parameters
committing are protected by damon_sysfs_lock to avoid the sysfs files
being destroyed while any of the parameters are being read. But the
user-driven direct reads and writes are not protected by any lock, while
the write is deallocating the memcg_path-pointing buffer. As a result,
the readers could read the already freed buffer (user-after-free). Note
that the user-reads don't race when the same open file is used by the
writer, due to kernfs's open file locking. Nonetheless, doing the reads
and writes with separate open files would be common. Fix it by protecting
both the user-direct reads and writes with damon_sysfs_lock.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-05-28
In the Linux kernel, the following vulnerability has been resolved:
wifi: b43: enforce bounds check on firmware key index in b43_rx()
The firmware-controlled key index in b43_rx() can exceed the dev->key[]
array size (58 entries). The existing B43_WARN_ON is non-enforcing in
production builds, allowing an out-of-bounds read.
Make the B43_WARN_ON check enforcing by dropping the frame when the
firmware returns an invalid key index.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-05-28