Linux: >> Linux Kernel >> 6.6.49 Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
net_sched: prio: fix a race in prio_tune()
Gerrard Tai reported a race condition in PRIO, whenever SFQ perturb timer
fires at the wrong time.
The race is as follows:
CPU 0 CPU 1
[1]: lock root
[2]: qdisc_tree_flush_backlog()
[3]: unlock root
|
| [5]: lock root
| [6]: rehash
| [7]: qdisc_tree_reduce_backlog()
|
[4]: qdisc_put()
This can be abused to underflow a parent's qlen.
Calling qdisc_purge_queue() instead of qdisc_tree_flush_backlog()
should fix the race, because all packets will be purged from the qdisc
before releasing the lock.
CVSS Score
4.7
EPSS Score
0.0
Published
2025-06-20
In the Linux kernel, the following vulnerability has been resolved:
platform/x86: dell-wmi-sysman: Avoid buffer overflow in current_password_store()
If the 'buf' array received from the user contains an empty string, the
'length' variable will be zero. Accessing the 'buf' array element with
index 'length - 1' will result in a buffer overflow.
Add a check for an empty string.
Found by Linux Verification Center (linuxtesting.org) with SVACE.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-06-18
In the Linux kernel, the following vulnerability has been resolved:
ALSA: pcm: Fix race of buffer access at PCM OSS layer
The PCM OSS layer tries to clear the buffer with the silence data at
initialization (or reconfiguration) of a stream with the explicit call
of snd_pcm_format_set_silence() with runtime->dma_area. But this may
lead to a UAF because the accessed runtime->dma_area might be freed
concurrently, as it's performed outside the PCM ops.
For avoiding it, move the code into the PCM core and perform it inside
the buffer access lock, so that it won't be changed during the
operation.
CVSS Score
4.7
EPSS Score
0.0
Published
2025-06-18
In the Linux kernel, the following vulnerability has been resolved:
crypto: algif_hash - fix double free in hash_accept
If accept(2) is called on socket type algif_hash with
MSG_MORE flag set and crypto_ahash_import fails,
sk2 is freed. However, it is also freed in af_alg_release,
leading to slab-use-after-free error.
CVSS Score
7.8
EPSS Score
0.0
Published
2025-06-18
In the Linux kernel, the following vulnerability has been resolved:
drm/amd/display: Increase block_sequence array size
[Why]
It's possible to generate more than 50 steps in hwss_build_fast_sequence,
for example with a 6-pipe asic where all pipes are in one MPC chain. This
overflows the block_sequence buffer and corrupts block_sequence_steps,
causing a crash.
[How]
Expand block_sequence to 100 items. A naive upper bound on the possible
number of steps for a 6-pipe asic, ignoring the potential for steps to be
mutually exclusive, is 91 with current code, therefore 100 is sufficient.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-06-18
In the Linux kernel, the following vulnerability has been resolved:
spi-rockchip: Fix register out of bounds access
Do not write native chip select stuff for GPIO chip selects.
GPIOs can be numbered much higher than native CS.
Also, it makes no sense.
CVSS Score
7.1
EPSS Score
0.0
Published
2025-06-18
In the Linux kernel, the following vulnerability has been resolved:
PCI: endpoint: pci-epf-test: Fix double free that causes kernel to oops
Fix a kernel oops found while testing the stm32_pcie Endpoint driver
with handling of PERST# deassertion:
During EP initialization, pci_epf_test_alloc_space() allocates all BARs,
which are further freed if epc_set_bar() fails (for instance, due to no
free inbound window).
However, when pci_epc_set_bar() fails, the error path:
pci_epc_set_bar() ->
pci_epf_free_space()
does not clear the previous assignment to epf_test->reg[bar].
Then, if the host reboots, the PERST# deassertion restarts the BAR
allocation sequence with the same allocation failure (no free inbound
window), creating a double free situation since epf_test->reg[bar] was
deallocated and is still non-NULL.
Thus, make sure that pci_epf_alloc_space() and pci_epf_free_space()
invocations are symmetric, and as such, set epf_test->reg[bar] to NULL
when memory is freed.
[kwilczynski: commit log]
CVSS Score
7.8
EPSS Score
0.0
Published
2025-06-18
In the Linux kernel, the following vulnerability has been resolved:
x86/mm: Check return value from memblock_phys_alloc_range()
At least with CONFIG_PHYSICAL_START=0x100000, if there is < 4 MiB of
contiguous free memory available at this point, the kernel will crash
and burn because memblock_phys_alloc_range() returns 0 on failure,
which leads memblock_phys_free() to throw the first 4 MiB of physical
memory to the wolves.
At a minimum it should fail gracefully with a meaningful diagnostic,
but in fact everything seems to work fine without the weird reserve
allocation.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-06-18
In the Linux kernel, the following vulnerability has been resolved:
libnvdimm/labels: Fix divide error in nd_label_data_init()
If a faulty CXL memory device returns a broken zero LSA size in its
memory device information (Identify Memory Device (Opcode 4000h), CXL
spec. 3.1, 8.2.9.9.1.1), a divide error occurs in the libnvdimm
driver:
Oops: divide error: 0000 [#1] PREEMPT SMP NOPTI
RIP: 0010:nd_label_data_init+0x10e/0x800 [libnvdimm]
Code and flow:
1) CXL Command 4000h returns LSA size = 0
2) config_size is assigned to zero LSA size (CXL pmem driver):
drivers/cxl/pmem.c: .config_size = mds->lsa_size,
3) max_xfer is set to zero (nvdimm driver):
drivers/nvdimm/label.c: max_xfer = min_t(size_t, ndd->nsarea.max_xfer, config_size);
4) A subsequent DIV_ROUND_UP() causes a division by zero:
drivers/nvdimm/label.c: /* Make our initial read size a multiple of max_xfer size */
drivers/nvdimm/label.c: read_size = min(DIV_ROUND_UP(read_size, max_xfer) * max_xfer,
drivers/nvdimm/label.c- config_size);
Fix this by checking the config size parameter by extending an
existing check.
CVSS Score
5.5
EPSS Score
0.0
Published
2025-06-18
In the Linux kernel, the following vulnerability has been resolved:
block: fix race between set_blocksize and read paths
With the new large sector size support, it's now the case that
set_blocksize can change i_blksize and the folio order in a manner that
conflicts with a concurrent reader and causes a kernel crash.
Specifically, let's say that udev-worker calls libblkid to detect the
labels on a block device. The read call can create an order-0 folio to
read the first 4096 bytes from the disk. But then udev is preempted.
Next, someone tries to mount an 8k-sectorsize filesystem from the same
block device. The filesystem calls set_blksize, which sets i_blksize to
8192 and the minimum folio order to 1.
Now udev resumes, still holding the order-0 folio it allocated. It then
tries to schedule a read bio and do_mpage_readahead tries to create
bufferheads for the folio. Unfortunately, blocks_per_folio == 0 because
the page size is 4096 but the blocksize is 8192 so no bufferheads are
attached and the bh walk never sets bdev. We then submit the bio with a
NULL block device and crash.
Therefore, truncate the page cache after flushing but before updating
i_blksize. However, that's not enough -- we also need to lock out file
IO and page faults during the update. Take both the i_rwsem and the
invalidate_lock in exclusive mode for invalidations, and in shared mode
for read/write operations.
I don't know if this is the correct fix, but xfs/259 found it.
CVSS Score
4.7
EPSS Score
0.0
Published
2025-06-18