Linux: >> Linux Kernel >> 4.9.231 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
fbcon: check return value of con2fb_acquire_newinfo()
If fbcon_open() fails when called from con2fb_acquire_newinfo() then
info->fbcon_par pointer remains NULL which is later dereferenced.
Add check for return value of the function con2fb_acquire_newinfo() to
avoid it.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
pstore: ram_core: fix incorrect success return when vmap() fails
In persistent_ram_vmap(), vmap() may return NULL on failure.
If offset is non-zero, adding offset_in_page(start) causes the function
to return a non-NULL pointer even though the mapping failed.
persistent_ram_buffer_map() therefore incorrectly returns success.
Subsequent access to prz->buffer may dereference an invalid address
and cause crashes.
Add proper NULL checking for vmap() failures.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
dlm: validate length in dlm_search_rsb_tree
The len parameter in dlm_dump_rsb_name() is not validated and comes
from network messages. When it exceeds DLM_RESNAME_MAXLEN, it can
cause out-of-bounds write in dlm_search_rsb_tree().
Add length validation to prevent potential buffer overflow.
CVSS Score
9.8
EPSS Score
0.001
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
ALSA: mixer: oss: Add card disconnect checkpoints
ALSA OSS mixer layer calls the kcontrol ops rather individually, and
pending calls might be not always caught at disconnecting the device.
For avoiding the potential UAF scenarios, add sanity checks of the
card disconnection at each entry point of OSS mixer accesses. The
rwsem is taken just before that check, hence the rest context should
be covered by that properly.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
jfs: nlink overflow in jfs_rename
If nlink is maximal for a directory (-1) and inside that directory you
perform a rename for some child directory (not moving from the parent),
then the nlink of the first directory is first incremented and later
decremented. Normally this is fine, but when nlink = -1 this causes a
wrap around to 0, and then drop_nlink issues a warning.
After applying the patch syzbot no longer issues any warnings. I also
ran some basic fs tests to look for any regressions.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
memory: mtk-smi: fix device leak on larb probe
Make sure to drop the reference taken when looking up the SMI device
during larb probe on late probe failure (e.g. probe deferral) and on
driver unbind.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
wifi: wl1251: validate packet IDs before indexing tx_frames
wl1251_tx_packet_cb() uses the firmware completion ID directly to index
the fixed 16-entry wl->tx_frames[] array. The ID is a raw u8 from the
completion block, and the callback does not currently verify that it
fits the array before dereferencing it.
Reject completion IDs that fall outside wl->tx_frames[] and keep the
existing NULL check in the same guard. This keeps the fix local to the
trust boundary and avoids touching the rest of the completion flow.
CVSS Score
8.8
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
netfilter: ctnetlink: ensure safe access to master conntrack
Holding reference on the expectation is not sufficient, the master
conntrack object can just go away, making exp->master invalid.
To access exp->master safely:
- Grab the nf_conntrack_expect_lock, this gets serialized with
clean_from_lists() which also holds this lock when the master
conntrack goes away.
- Hold reference on master conntrack via nf_conntrack_find_get().
Not so easy since the master tuple to look up for the master conntrack
is not available in the existing problematic paths.
This patch goes for extending the nf_conntrack_expect_lock section
to address this issue for simplicity, in the cases that are described
below this is just slightly extending the lock section.
The add expectation command already holds a reference to the master
conntrack from ctnetlink_create_expect().
However, the delete expectation command needs to grab the spinlock
before looking up for the expectation. Expand the existing spinlock
section to address this to cover the expectation lookup. Note that,
the nf_ct_expect_iterate_net() calls already grabs the spinlock while
iterating over the expectation table, which is correct.
The get expectation command needs to grab the spinlock to ensure master
conntrack does not go away. This also expands the existing spinlock
section to cover the expectation lookup too. I needed to move the
netlink skb allocation out of the spinlock to keep it GFP_KERNEL.
For the expectation events, the IPEXP_DESTROY event is already delivered
under the spinlock, just move the delivery of IPEXP_NEW under the
spinlock too because the master conntrack event cache is reached through
exp->master.
While at it, add lockdep notations to help identify what codepaths need
to grab the spinlock.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
btrfs: tracepoints: get correct superblock from dentry in event btrfs_sync_file()
If overlay is used on top of btrfs, dentry->d_sb translates to overlay's
super block and fsid assignment will lead to a crash.
Use file_inode(file)->i_sb to always get btrfs_sb.
CVSS Score
9.1
EPSS Score
0.001
Published
2026-05-06
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix zero size inode with non-zero size after log replay
When logging that an inode exists, as part of logging a new name or
logging new dir entries for a directory, we always set the generation of
the logged inode item to 0. This is to signal during log replay (in
overwrite_item()), that we should not set the i_size since we only logged
that an inode exists, so the i_size of the inode in the subvolume tree
must be preserved (as when we log new names or that an inode exists, we
don't log extents).
This works fine except when we have already logged an inode in full mode
or it's the first time we are logging an inode created in a past
transaction, that inode has a new i_size of 0 and then we log a new name
for the inode (due to a new hardlink or a rename), in which case we log
an i_size of 0 for the inode and a generation of 0, which causes the log
replay code to not update the inode's i_size to 0 (in overwrite_item()).
An example scenario:
mkdir /mnt/dir
xfs_io -f -c "pwrite 0 64K" /mnt/dir/foo
sync
xfs_io -c "truncate 0" -c "fsync" /mnt/dir/foo
ln /mnt/dir/foo /mnt/dir/bar
xfs_io -c "fsync" /mnt/dir
<power fail>
After log replay the file remains with a size of 64K. This is because when
we first log the inode, when we fsync file foo, we log its current i_size
of 0, and then when we create a hard link we log again the inode in exists
mode (LOG_INODE_EXISTS) but we set a generation of 0 for the inode item we
add to the log tree, so during log replay overwrite_item() sees that the
generation is 0 and i_size is 0 so we skip updating the inode's i_size
from 64K to 0.
Fix this by making sure at fill_inode_item() we always log the real
generation of the inode if it was logged in the current transaction with
the i_size we logged before. Also if an inode created in a previous
transaction is logged in exists mode only, make sure we log the i_size
stored in the inode item located from the commit root, so that if we log
multiple times that the inode exists we get the correct i_size.
A test case for fstests will follow soon.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-05-06