Linux: >> Linux Kernel >> 5.11.5 Security Vulnerabilities
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:
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
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix same-register dst/src OOB read and pointer leak in sock_ops
When a BPF sock_ops program accesses ctx fields with dst_reg == src_reg,
the SOCK_OPS_GET_SK() and SOCK_OPS_GET_FIELD() macros fail to zero the
destination register in the !fullsock / !locked_tcp_sock path.
Both macros borrow a temporary register to check is_fullsock /
is_locked_tcp_sock when dst_reg == src_reg, because dst_reg holds the
ctx pointer. When the check is false (e.g., TCP_NEW_SYN_RECV state with
a request_sock), dst_reg should be zeroed but is not, leaving the stale
ctx pointer:
- SOCK_OPS_GET_SK: dst_reg retains the ctx pointer, passes NULL checks
as PTR_TO_SOCKET_OR_NULL, and can be used as a bogus socket pointer,
leading to stack-out-of-bounds access in helpers like
bpf_skc_to_tcp6_sock().
- SOCK_OPS_GET_FIELD: dst_reg retains the ctx pointer which the
verifier believes is a SCALAR_VALUE, leaking a kernel pointer.
Fix both macros by:
- Changing JMP_A(1) to JMP_A(2) in the fullsock path to skip the
added instruction.
- Adding BPF_MOV64_IMM(si->dst_reg, 0) after the temp register
restore in the !fullsock path, placed after the restore because
dst_reg == src_reg means we need src_reg intact to read ctx->temp.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
sctp: disable BH before calling udp_tunnel_xmit_skb()
udp_tunnel_xmit_skb() / udp_tunnel6_xmit_skb() are expected to run with
BH disabled. After commit 6f1a9140ecda ("add xmit recursion limit to
tunnel xmit functions"), on the path:
udp(6)_tunnel_xmit_skb() -> ip(6)tunnel_xmit()
dev_xmit_recursion_inc()/dec() must stay balanced on the same CPU.
Without local_bh_disable(), the context may move between CPUs, which can
break the inc/dec pairing. This may lead to incorrect recursion level
detection and cause packets to be dropped in ip(6)_tunnel_xmit() or
__dev_queue_xmit().
Fix it by disabling BH around both IPv4 and IPv6 SCTP UDP xmit paths.
In my testing, after enabling the SCTP over UDP:
# ip net exec ha sysctl -w net.sctp.udp_port=9899
# ip net exec ha sysctl -w net.sctp.encap_port=9899
# ip net exec hb sysctl -w net.sctp.udp_port=9899
# ip net exec hb sysctl -w net.sctp.encap_port=9899
# ip net exec ha iperf3 -s
- without this patch:
# ip net exec hb iperf3 -c 192.168.0.1 --sctp
[ 5] 0.00-10.00 sec 37.2 MBytes 31.2 Mbits/sec sender
[ 5] 0.00-10.00 sec 37.1 MBytes 31.1 Mbits/sec receiver
- with this patch:
# ip net exec hb iperf3 -c 192.168.0.1 --sctp
[ 5] 0.00-10.00 sec 3.14 GBytes 2.69 Gbits/sec sender
[ 5] 0.00-10.00 sec 3.14 GBytes 2.69 Gbits/sec receiver
CVSS Score
7.5
EPSS Score
0.003
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: l2cap: Add missing chan lock in l2cap_ecred_reconf_rsp
l2cap_ecred_reconf_rsp() calls l2cap_chan_del() without holding
l2cap_chan_lock(). Every other l2cap_chan_del() caller in the file
acquires the lock first. A remote BLE device can send a crafted
L2CAP ECRED reconfiguration response to corrupt the channel list
while another thread is iterating it.
Add l2cap_chan_hold() and l2cap_chan_lock() before l2cap_chan_del(),
and l2cap_chan_unlock() and l2cap_chan_put() after, matching the
pattern used in l2cap_ecred_conn_rsp() and l2cap_conn_del().
CVSS Score
8.8
EPSS Score
0.003
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
dm cache policy smq: fix missing locks in invalidating cache blocks
In passthrough mode, the policy invalidate_mapping operation is called
simultaneously from multiple workers, thus it should be protected by a
lock. Otherwise, we might end up with data races on the allocated blocks
counter, or even use-after-free issues with internal data structures
when doing concurrent writes.
Note that the existing FIXME in smq_invalidate_mapping() doesn't affect
passthrough mode since migration tasks don't exist there, but would need
attention if supporting fast device shrinking via suspend/resume without
target reloading.
Reproduce steps:
1. Create a cache device consisting of 1024 cache entries
dmsetup create cmeta --table "0 8192 linear /dev/sdc 0"
dmsetup create cdata --table "0 131072 linear /dev/sdc 8192"
dmsetup create corig --table "0 262144 linear /dev/sdc 262144"
dd if=/dev/zero of=/dev/mapper/cmeta bs=4k count=1 oflag=direct
dmsetup create cache --table "0 262144 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 writethrough smq 0"
2. Populate the cache, and record the number of cached blocks
fio --name=populate --filename=/dev/mapper/cache --rw=randwrite --bs=4k \
--size=64m --direct=1
nr_cached=$(dmsetup status cache | awk '{split($7, a, "/"); print a[1]}')
3. Reload the cache into passthrough mode
dmsetup suspend cache
dmsetup reload cache --table "0 262144 cache /dev/mapper/cmeta \
/dev/mapper/cdata /dev/mapper/corig 128 2 metadata2 passthrough smq 0"
dmsetup resume cache
4. Write to the passthrough cache. By setting multiple jobs with I/O
size equal to the cache block size, cache blocks are invalidated
concurrently from different workers.
fio --filename=/dev/mapper/cache --name=test --rw=randwrite --bs=64k \
--direct=1 --numjobs=2 --randrepeat=0 --size=64m
5. Check if demoted matches cached block count. These numbers should
match but may differ due to the data race.
nr_demoted=$(dmsetup status cache | awk '{print $12}')
echo "$nr_cached, $nr_demoted"
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-24