Linux: >> Linux Kernel >> 5.8.7 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
RDMA/umem: Fix truncation for block sizes >= 4G
When the iommu is used the linearization of the mapping can give a single
block that is very large split across multiple SG entries.
When __rdma_block_iter_next() reassembles the split SG entries it is
overflowing the 32 bit stack values and computed the wrong DMA addresses
for blocks after the truncation.
Use the right types to hold DMA addresses.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nft_fib: fix stale stack leak via the OIFNAME register
For NFT_FIB_RESULT_OIFNAME the destination register is declared with
len = IFNAMSIZ (four 32-bit registers), but on the lookup-fail,
RTN_LOCAL and oif-mismatch paths nft_fib{4,6}_eval() only writes one
register via "*dest = 0". The remaining three registers are left as
whatever was on the stack in nft_do_chain()'s struct nft_regs, and a
downstream expression that loads the register span can leak that
uninitialised kernel stack to userspace.
The NFTA_FIB_F_PRESENT existence check has the same shape: it is only
meaningful for NFT_FIB_RESULT_OIF, yet it was accepted for any result type
while the eval stores a single byte via nft_reg_store8(), leaving the rest
of the declared span stale.
Fix both:
- replace the bare "*dest = 0" in the eval with nft_fib_store_result(),
which strscpy_pad()s the whole IFNAMSIZ for OIFNAME (and is already
used on the other early-return path), and
- restrict NFTA_FIB_F_PRESENT to NFT_FIB_RESULT_OIF and declare its
destination as a single u8, so the marked span matches the one byte
the eval writes.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Fix NULL deref and buffer over-read in SDP debugfs
[Why & How]
dp_sdp_message_debugfs_write() dereferences connector->base.state->crtc
without checking for NULL. A connector can be connected but not bound to
any CRTC (e.g. after hot-plug before the next atomic commit), causing a
kernel crash when writing to the sdp_message debugfs node.
The function also ignores the user-provided size argument and always
passes 36 bytes to copy_from_user(), reading past the user buffer when
size < 36.
Fix both issues by:
- Returning -ENODEV when connector->base.state or state->crtc is NULL
- Clamping write_size to min(size, sizeof(data))
(cherry picked from commit 6ab4c36a522842ff70474a1c0af2e40e50fc8300)
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Clamp VBIOS HDMI retimer register count to array size
[Why & How]
The VBIOS integrated info tables (v1_11 and v2_1) contain HdmiRegNum and
Hdmi6GRegNum fields that are used as loop bounds when copying retimer I2C
register settings into fixed-size arrays (dp*_ext_hdmi_reg_settings[9]
and dp*_ext_hdmi_6g_reg_settings[3]). These u8 fields are not validated
before use, so a malformed VBIOS can specify values up to 255, causing an
out-of-bounds heap write during driver probe.
Clamp each register count to the destination array size using min_t()
before the copy loops, in both get_integrated_info_v11() and
get_integrated_info_v2_1().
(cherry picked from commit 5a7f0ef90195940c54b0f5bb85b87da55f038c69)
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
drbd: Balance RCU calls in drbd_adm_dump_devices()
Make drbd_adm_dump_devices() call rcu_read_lock() before
rcu_read_unlock() is called. This has been detected by the Clang
thread-safety analyzer.
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
fs/mbcache: cancel shrink work before destroying the cache
mb_cache_destroy() calls shrinker_free() and then frees all cache
entries and the cache itself, but it does not cancel the pending
c_shrink_work work item first.
If mb_cache_entry_create() schedules c_shrink_work via schedule_work()
and the work item is still pending or running when mb_cache_destroy()
runs, mb_cache_shrink_worker() will access the cache after its memory
has been freed, causing a use-after-free.
This is only reachable by a privileged user (root or CAP_SYS_ADMIN)
who can trigger the last put of a mounted ext2/ext4/ocfs2 filesystem.
Cancel the work item with cancel_work_sync() before calling
shrinker_free(), ensuring the worker has finished and will not be
rescheduled before the cache is torn down.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
fs/omfs: reject s_sys_blocksize smaller than OMFS_DIR_START
omfs_fill_super() rejects oversized s_sys_blocksize values (> PAGE_SIZE),
but it does not reject values smaller than OMFS_DIR_START (0x1b8 = 440).
Later, omfs_make_empty() uses
sbi->s_sys_blocksize - OMFS_DIR_START
as the length argument to memset(). Since s_sys_blocksize is u32,
a crafted filesystem image with s_sys_blocksize < OMFS_DIR_START causes
an unsigned underflow there, wrapping to a value near 2^32. That drives
a ~4 GiB memset() from bh->b_data + OMFS_DIR_START and overwrites kernel
memory far beyond the backing block buffer.
Add the corresponding lower-bound check alongside the existing upper-bound
check in omfs_fill_super(), so that malformed images are rejected during
superblock validation before any filesystem data is processed.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
s390/cio: use generic driver_override infrastructure
When a driver is probed through __driver_attach(), the bus' match()
callback is called without the device lock held, thus accessing the
driver_override field without a lock, which can cause a UAF.
Fix this by using the driver-core driver_override infrastructure taking
care of proper locking internally.
Note that calling match() from __driver_attach() without the device lock
held is intentional. [1]
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
PCI: use generic driver_override infrastructure
When a driver is probed through __driver_attach(), the bus' match()
callback is called without the device lock held, thus accessing the
driver_override field without a lock, which can cause a UAF.
Fix this by using the driver-core driver_override infrastructure taking
care of proper locking internally.
Note that calling match() from __driver_attach() without the device lock
held is intentional. [1]
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-24
In the Linux kernel, the following vulnerability has been resolved:
btrfs: fix deadlock between reflink and transaction commit when using flushoncommit
When using the flushoncommit mount option, we can have a deadlock between
a transaction commit and a reflink operation that copied an inline extent
to an offset beyond the current i_size of the destination node.
The deadlock happens like this:
1) Task A clones an inline extent from inode X to an offset of inode Y
that is beyond Y's current i_size. This means we copied the inline
extent's data to a folio of inode Y that is beyond its EOF, using a
call to copy_inline_to_page();
2) Task B starts a transaction commit and calls
btrfs_start_delalloc_flush() to flush delalloc;
3) The delalloc flushing sees the new dirty folio of inode Y and when it
attempts to flush it, it ends up at extent_writepage() and sees that
the offset of the folio is beyond the i_size of inode Y, so it attempts
to invalidate the folio by calling folio_invalidate(), which ends up at
btrfs' folio invalidate callback - btrfs_invalidate_folio(). There it
tries to lock the folio's range in inode Y's extent io tree, but it
blocks since it's currently locked by task A - during a reflink we lock
the inodes and the source and destination ranges after flushing all
delalloc and waiting for ordered extent completion - after that we
don't expect to have dirty folios in the ranges, the exception is if
we have to copy an inline extent's data (because the destination offset
is not zero);
4) Task A then attempts to start a transaction to update the inode item,
and then it's blocked since the current transaction is in the
TRANS_STATE_COMMIT_START state. Therefore task A has to wait for the
current transaction to become unblocked (its state >=
TRANS_STATE_UNBLOCKED).
So task A is waiting for the transaction commit done by task B, and
the later waiting on the extent lock of inode Y that is currently
held by task A.
Syzbot recently reported this with the following stack traces:
INFO: task kworker/u8:7:1053 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:7 state:D stack:23520 pid:1053 tgid:1053 ppid:2 task_flags:0x4208060 flags:0x00080000
Workqueue: writeback wb_workfn (flush-btrfs-46)
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5298 [inline]
__schedule+0x1553/0x5240 kernel/sched/core.c:6911
__schedule_loop kernel/sched/core.c:6993 [inline]
schedule+0x164/0x360 kernel/sched/core.c:7008
wait_extent_bit fs/btrfs/extent-io-tree.c:811 [inline]
btrfs_lock_extent_bits+0x59c/0x700 fs/btrfs/extent-io-tree.c:1914
btrfs_lock_extent fs/btrfs/extent-io-tree.h:152 [inline]
btrfs_invalidate_folio+0x43d/0xc40 fs/btrfs/inode.c:7704
extent_writepage fs/btrfs/extent_io.c:1852 [inline]
extent_write_cache_pages fs/btrfs/extent_io.c:2580 [inline]
btrfs_writepages+0x12ff/0x2440 fs/btrfs/extent_io.c:2713
do_writepages+0x32e/0x550 mm/page-writeback.c:2554
__writeback_single_inode+0x133/0x11a0 fs/fs-writeback.c:1750
writeback_sb_inodes+0x995/0x19d0 fs/fs-writeback.c:2042
wb_writeback+0x456/0xb70 fs/fs-writeback.c:2227
wb_do_writeback fs/fs-writeback.c:2374 [inline]
wb_workfn+0x41a/0xf60 fs/fs-writeback.c:2414
process_one_work kernel/workqueue.c:3276 [inline]
process_scheduled_works+0xb6e/0x18c0 kernel/workqueue.c:3359
worker_thread+0xa53/0xfc0 kernel/workqueue.c:3440
kthread+0x388/0x470 kernel/kthread.c:436
ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
INFO: task syz.4.64:6910 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.64 state:D stack:22752 pid:6910 tgid:
---truncated---
CVSS Score
5.5
EPSS Score
0.001
Published
2026-06-24