Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
zram: fix use-after-free in zram_bvec_write_partial()
zram_read_page() picks the sync or async backing device read path based on
whether the parent bio is NULL. zram_bvec_write_partial() passes its
parent bio down, so for ZRAM_WB slots the read is dispatched
asynchronously and zram_read_page() returns 0 while the bio is still in
flight. The caller then runs memcpy_from_bvec(), zram_write_page() and
__free_page() on the buffer, leaving the async read to write into a freed
page.
zram_bvec_read_partial() was switched to NULL in commit 4e3c87b9421d
("zram: fix synchronous reads") for the same reason; the write_partial
counterpart was missed.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
fuse: limit FUSE_NOTIFY_RETRIEVE to uptodate folios
FUSE_NOTIFY_RETRIEVE must be limited to uptodate folios; !uptodate folios
can contain uninitialized data.
Since FUSE_NOTIFY_RETRIEVE is intended to only return data that is already
in the page cache and not wait for data from the FUSE daemon, treat
!uptodate folios as if they weren't present.
This only has security impact on systems that don't enable automatic
zero-initialization of all page allocations via
CONFIG_INIT_ON_ALLOC_DEFAULT_ON or init_on_alloc=1.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
fuse: reject fuse_notify() pagecache ops on directories
The operations FUSE_NOTIFY_STORE and FUSE_NOTIFY_RETRIEVE allow the
FUSE daemon to actively write/read pagecache contents.
For directories with FOPEN_CACHE_DIR, the pagecache is used as
kernel-internal cache storage, and userspace is not supposed to have
direct access to this cache - in particular, fuse_parse_cache() will hit
WARN_ON() if the cache contains bogus data.
Reject FUSE_NOTIFY_STORE and FUSE_NOTIFY_RETRIEVE on anything other than
regular files with -EINVAL.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
accel/ethosu: reject NPU_OP_RESIZE commands from userspace
NPU_OP_RESIZE is a U85-only command that the driver does not yet
implement. The existing WARN_ON(1) placeholder fires unconditionally
whenever userspace submits this command via DRM_IOCTL_ETHOSU_GEM_CREATE,
causing unbounded kernel log spam.
If panic_on_warn is set the kernel panics, giving any unprivileged user
with access to the DRM device a trivial denial-of-service primitive.
Replace the WARN_ON(1) with an explicit -EINVAL return so the ioctl
rejects the command before it reaches hardware.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
accel/ethosu: reject DMA commands with uninitialized length
cmd_state_init() initializes the command state with memset(0xff),
leaving dma->len at U64_MAX to signal missing setup. The only setter
is NPU_SET_DMA0_LEN; if userspace omits this command and issues
NPU_OP_DMA_START, dma->len remains U64_MAX.
In dma_length(), a positive stride added to U64_MAX wraps to a small
value. With size0 == 1, check_mul_overflow() does not trigger and
dma_length() returns 0 instead of U64_MAX. The caller's U64_MAX check
then passes, region_size[] stays 0, and the bounds check in
ethosu_job.c is bypassed, allowing hardware to execute DMA with stale
physical addresses.
Fix by checking for U64_MAX at the start of dma_length() before any
arithmetic, consistent with the sentinel value used throughout the
driver to detect uninitialized fields.
CVSS Score
8.8
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
accel/ethosu: fix arithmetic issues in dma_length()
dma_length() derives DMA region usage from command stream values and
updates region_size[]:
len = ((len + stride[0]) * size0 + stride[1]) * size1
region_size[region] = max(..., len + dma->offset)
Several arithmetic issues can corrupt the derived region size:
- signed stride values may underflow when added to len
- intermediate multiplications may overflow
- len + dma->offset may overflow during region_size updates
- dma_length() error returns were not validated by the caller
region_size[] is later used by ethosu_job.c to validate command stream
accesses against GEM buffer sizes. Arithmetic wraparound can therefore
under-report region usage and bypass the bounds validation.
Fix by validating signed additions, using overflow helpers for
multiplications and offset updates, and propagating dma_length()
failures to the caller.
CVSS Score
8.8
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
accel/ethosu: fix IFM region index out-of-bounds in command stream parser
NPU_SET_IFM_REGION extracts the region index with param & 0x7f, giving
a maximum value of 127. However region_size[] and output_region[] in
struct ethosu_validated_cmdstream_info are both sized to
NPU_BASEP_REGION_MAX (8), giving valid indices [0..7].
Every other region assignment in the same switch uses param & 0x7:
NPU_SET_OFM_REGION: st.ofm.region = param & 0x7;
NPU_SET_IFM2_REGION: st.ifm2.region = param & 0x7;
NPU_SET_WEIGHT_REGION: st.weight[0].region = param & 0x7;
NPU_SET_SCALE_REGION: st.scale[0].region = param & 0x7;
The 0x7f mask on IFM is inconsistent and appears to be a typo.
feat_matrix_length() and calc_sizes() use the region index directly
as an array subscript into the kzalloc'd info struct:
info->region_size[fm->region] = max(...);
A userspace caller supplying NPU_SET_IFM_REGION with param > 7 causes
a write up to 127*8 = 1016 bytes past the start of region_size[],
corrupting adjacent kernel heap data.
Fix by applying the same & 0x7 mask used by all other region
assignments.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
accel/ethosu: fix OOB write in ethosu_gem_cmdstream_copy_and_validate()
The command stream parsing loop increments the index variable a second
time when a 64-bit command word is encountered (bit 14 set), but does
not re-check the loop bound before writing the second word:
for (i = 0; i < size / 4; i++) {
bocmds[i] = cmds[0];
if (cmd & 0x4000) {
i++;
bocmds[i] = cmds[1]; /* unchecked */
}
}
The buffer bocmds is backed by a DMA allocation of exactly size bytes
from drm_gem_dma_create(ddev, size), giving valid indices [0, size/4-1].
When i == size/4 - 1 on entry to an iteration and bit 14 of cmds[0] is
set, bocmds[size/4-1] is written in bounds, i is then incremented to
size/4, and bocmds[size/4] writes four bytes past the end of the
allocation.
Userspace controls both the buffer contents and the size argument via
the ioctl, making this a userspace-triggerable heap out-of-bounds write.
Fix by checking the incremented index against the buffer bound before
the second write and returning -EINVAL if the buffer is too small to
contain the extended command.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
ovl: keep err zero after successful ovl_cache_get()
ovl_iterate_merged() stores PTR_ERR(cache) in err before checking
IS_ERR(cache). On success err holds the truncated cache pointer and
can be returned as a bogus non-zero error.
The syzbot reproducer reaches this through overlay-on-overlay readdir:
getdents64
iterate_dir(outer overlay file)
ovl_iterate_merged()
ovl_cache_get()
ovl_dir_read_merged()
ovl_dir_read()
iterate_dir(inner overlay file)
ovl_iterate_merged()
Only compute PTR_ERR(cache) on the error path.
CVSS Score
7.8
EPSS Score
0.001
Published
2026-06-25
In the Linux kernel, the following vulnerability has been resolved:
inet: frags: fix use-after-free caused by the fqdir_pre_exit() flush
On netns teardown, fqdir_pre_exit() walks the fqdir rhashtable and
flushes every fragment queue that is not yet complete using
inet_frag_queue_flush(). That helper frees all the skbs queued on the
fragment queue but does not set INET_FRAG_COMPLETE, and leaves
q->fragments_tail and q->last_run_head pointing at the freed skbs.
The queue itself stays in the rhashtable.
fqdir_pre_exit() first lowers high_thresh to 0 to stop new queue lookups,
but it cannot stop a fragment that already obtained the queue through
inet_frag_find() earlier and stalled just before taking the queue lock.
Once that fragment resumes after the flush and takes the queue lock,
it passes the INET_FRAG_COMPLETE check and then dereferences the freed
fragments_tail. inet_frag_queue_insert() reads FRAG_CB() and ->len of
that pointer and, on the append path, writes ->next_frag, causing a
slab use-after-free. IPv6, nf_conntrack_reasm6 and 6lowpan reassembly
share the same flush path and are affected as well.
Reset rb_fragments, fragments_tail and last_run_head in
inet_frag_queue_flush() so a flushed queue no longer points at the
freed skbs. A fragment that resumes after the flush and takes the
queue lock then finds an empty queue and starts a new run instead of
dereferencing the freed fragments_tail. ip_frag_reinit() already
performed this reset after its own flush, so drop the now duplicate
code there.
CVSS Score
9.8
EPSS Score
0.003
Published
2026-06-25