Linux: >> Linux Kernel >> 6.1.9 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
net/sched: Restrict conditions for adding duplicating netems to qdisc tree
netem_enqueue's duplication prevention logic breaks when a netem
resides in a qdisc tree with other netems - this can lead to a
soft lockup and OOM loop in netem_dequeue, as seen in [1].
Ensure that a duplicating netem cannot exist in a tree with other
netems.
Previous approaches suggested in discussions in chronological order:
1) Track duplication status or ttl in the sk_buff struct. Considered
too specific a use case to extend such a struct, though this would
be a resilient fix and address other previous and potential future
DOS bugs like the one described in loopy fun [2].
2) Restrict netem_enqueue recursion depth like in act_mirred with a
per cpu variable. However, netem_dequeue can call enqueue on its
child, and the depth restriction could be bypassed if the child is a
netem.
3) Use the same approach as in 2, but add metadata in netem_skb_cb
to handle the netem_dequeue case and track a packet's involvement
in duplication. This is an overly complex approach, and Jamal
notes that the skb cb can be overwritten to circumvent this
safeguard.
4) Prevent the addition of a netem to a qdisc tree if its ancestral
path contains a netem. However, filters and actions can cause a
packet to change paths when re-enqueued to the root from netem
duplication, leading us to the current solution: prevent a
duplicating netem from inhabiting the same tree as other netems.
[1] https://lore.kernel.org/netdev/8DuRWwfqjoRDLDmBMlIfbrsZg9Gx50DHJc1ilxsEBNe2D6NMoigR_eIRIG0LOjMc3r10nUUZtArXx4oZBIdUfZQrwjcQhdinnMis_0G7VEk=@willsroot.io/
[2] https://lwn.net/Articles/719297/
CVSS Score
5.5
EPSS Score
0.0
Published
2025-08-19
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: not allow guest user on multichannel
This patch return STATUS_NOT_SUPPORTED if binding session is guest.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix out-of-bound read in smb2_write
ksmbd_smb2_check_message doesn't validate hdr->NextCommand. If
->NextCommand is bigger than Offset + Length of smb2 write, It will
allow oversized smb2 write length. It will cause OOB read in smb2_write.
CVSS Score
7.1
EPSS Score
0.0
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: validate session id and tree id in the compound request
This patch validate session id and tree id in compound request.
If first operation in the compound is SMB2 ECHO request, ksmbd bypass
session and tree validation. So work->sess and work->tcon could be NULL.
If secound request in the compound access work->sess or tcon, It cause
NULL pointer dereferecing error.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix out of bounds read in smb2_sess_setup
ksmbd does not consider the case of that smb2 session setup is
in compound request. If this is the second payload of the compound,
OOB read issue occurs while processing the first payload in
the smb2_sess_setup().
CVSS Score
7.1
EPSS Score
0.001
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: fix wrong next length validation of ea buffer in smb2_set_ea()
There are multiple smb2_ea_info buffers in FILE_FULL_EA_INFORMATION request
from client. ksmbd find next smb2_ea_info using ->NextEntryOffset of
current smb2_ea_info. ksmbd need to validate buffer length Before
accessing the next ea. ksmbd should check buffer length using buf_len,
not next variable. next is the start offset of current ea that got from
previous ea.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
ksmbd: call rcu_barrier() in ksmbd_server_exit()
racy issue is triggered the bug by racing between closing a connection
and rmmod. In ksmbd, rcu_barrier() is not called at module unload time,
so nothing prevents ksmbd from getting unloaded while it still has RCU
callbacks pending. It leads to trigger unintended execution of kernel
code locally and use to defeat protections such as Kernel Lockdown
CVSS Score
5.5
EPSS Score
0.001
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
ipv6: mcast: Delay put pmc->idev in mld_del_delrec()
pmc->idev is still used in ip6_mc_clear_src(), so as mld_clear_delrec()
does, the reference should be put after ip6_mc_clear_src() return.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
mptcp: plug races between subflow fail and subflow creation
We have races similar to the one addressed by the previous patch between
subflow failing and additional subflow creation. They are just harder to
trigger.
The solution is similar. Use a separate flag to track the condition
'socket state prevent any additional subflow creation' protected by the
fallback lock.
The socket fallback makes such flag true, and also receiving or sending
an MP_FAIL option.
The field 'allow_infinite_fallback' is now always touched under the
relevant lock, we can drop the ONCE annotation on write.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-08-16
In the Linux kernel, the following vulnerability has been resolved:
net: appletalk: Fix device refcount leak in atrtr_create()
When updating an existing route entry in atrtr_create(), the old device
reference was not being released before assigning the new device,
leading to a device refcount leak. Fix this by calling dev_put() to
release the old device reference before holding the new one.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-08-16