Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
af_unix: Give up GC if MSG_PEEK intervened.
Igor Ushakov reported that GC purged the receive queue of
an alive socket due to a race with MSG_PEEK with a nice repro.
This is the exact same issue previously fixed by commit
cbcf01128d0a ("af_unix: fix garbage collect vs MSG_PEEK").
After GC was replaced with the current algorithm, the cited
commit removed the locking dance in unix_peek_fds() and
reintroduced the same issue.
The problem is that MSG_PEEK bumps a file refcount without
interacting with GC.
Consider an SCC containing sk-A and sk-B, where sk-A is
close()d but can be recv()ed via sk-B.
The bad thing happens if sk-A is recv()ed with MSG_PEEK from
sk-B and sk-B is close()d while GC is checking unix_vertex_dead()
for sk-A and sk-B.
GC thread User thread
--------- -----------
unix_vertex_dead(sk-A)
-> true <------.
\
`------ recv(sk-B, MSG_PEEK)
invalidate !! -> sk-A's file refcount : 1 -> 2
close(sk-B)
-> sk-B's file refcount : 2 -> 1
unix_vertex_dead(sk-B)
-> true
Initially, sk-A's file refcount is 1 by the inflight fd in sk-B
recvq. GC thinks sk-A is dead because the file refcount is the
same as the number of its inflight fds.
However, sk-A's file refcount is bumped silently by MSG_PEEK,
which invalidates the previous evaluation.
At this moment, sk-B's file refcount is 2; one by the open fd,
and one by the inflight fd in sk-A. The subsequent close()
releases one refcount by the former.
Finally, GC incorrectly concludes that both sk-A and sk-B are dead.
One option is to restore the locking dance in unix_peek_fds(),
but we can resolve this more elegantly thanks to the new algorithm.
The point is that the issue does not occur without the subsequent
close() and we actually do not need to synchronise MSG_PEEK with
the dead SCC detection.
When the issue occurs, close() and GC touch the same file refcount.
If GC sees the refcount being decremented by close(), it can just
give up garbage-collecting the SCC.
Therefore, we only need to signal the race during MSG_PEEK with
a proper memory barrier to make it visible to the GC.
Let's use seqcount_t to notify GC when MSG_PEEK occurs and let
it defer the SCC to the next run.
This way no locking is needed on the MSG_PEEK side, and we can
avoid imposing a penalty on every MSG_PEEK unnecessarily.
Note that we can retry within unix_scc_dead() if MSG_PEEK is
detected, but we do not do so to avoid hung task splat from
abusive MSG_PEEK calls.
CVSS Score
4.7
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
Bluetooth: L2CAP: Fix accepting multiple L2CAP_ECRED_CONN_REQ
Currently the code attempts to accept requests regardless of the
command identifier which may cause multiple requests to be marked
as pending (FLAG_DEFER_SETUP) which can cause more than
L2CAP_ECRED_MAX_CID(5) to be allocated in l2cap_ecred_rsp_defer
causing an overflow.
The spec is quite clear that the same identifier shall not be used on
subsequent requests:
'Within each signaling channel a different Identifier shall be used
for each successive request or indication.'
https://www.bluetooth.com/wp-content/uploads/Files/Specification/HTML/Core-62/out/en/host/logical-link-control-and-adaptation-protocol-specification.html#UUID-32a25a06-4aa4-c6c7-77c5-dcfe3682355d
So this attempts to check if there are any channels pending with the
same identifier and rejects if any are found.
CVSS Score
8.8
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
xen/privcmd: restrict usage in unprivileged domU
The Xen privcmd driver allows to issue arbitrary hypercalls from
user space processes. This is normally no problem, as access is
usually limited to root and the hypervisor will deny any hypercalls
affecting other domains.
In case the guest is booted using secure boot, however, the privcmd
driver would be enabling a root user process to modify e.g. kernel
memory contents, thus breaking the secure boot feature.
The only known case where an unprivileged domU is really needing to
use the privcmd driver is the case when it is acting as the device
model for another guest. In this case all hypercalls issued via the
privcmd driver will target that other guest.
Fortunately the privcmd driver can already be locked down to allow
only hypercalls targeting a specific domain, but this mode can be
activated from user land only today.
The target domain can be obtained from Xenstore, so when not running
in dom0 restrict the privcmd driver to that target domain from the
beginning, resolving the potential problem of breaking secure boot.
This is XSA-482
---
V2:
- defer reading from Xenstore if Xenstore isn't ready yet (Jan Beulich)
- wait in open() if target domain isn't known yet
- issue message in case no target domain found (Jan Beulich)
CVSS Score
8.2
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
pinctrl: cirrus: cs42l43: Fix double-put in cs42l43_pin_probe()
devm_add_action_or_reset() already invokes the action on failure,
so the explicit put causes a double-put.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
Squashfs: check metadata block offset is within range
Syzkaller reports a "general protection fault in squashfs_copy_data"
This is ultimately caused by a corrupted index look-up table, which
produces a negative metadata block offset.
This is subsequently passed to squashfs_copy_data (via
squashfs_read_metadata) where the negative offset causes an out of bounds
access.
The fix is to check that the offset is within range in
squashfs_read_metadata. This will trap this and other cases.
CVSS Score
7.1
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
ice: Fix memory leak in ice_set_ringparam()
In ice_set_ringparam, tx_rings and xdp_rings are allocated before
rx_rings. If the allocation of rx_rings fails, the code jumps to
the done label leaking both tx_rings and xdp_rings. Furthermore, if
the setup of an individual Rx ring fails during the loop, the code jumps
to the free_tx label which releases tx_rings but leaks xdp_rings.
Fix this by introducing a free_xdp label and updating the error paths to
ensure both xdp_rings and tx_rings are properly freed if rx_rings
allocation or setup fails.
Compile tested only. Issue found using a prototype static analysis tool
and code review.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
tracing/dma: Cap dma_map_sg tracepoint arrays to prevent buffer overflow
The dma_map_sg tracepoint can trigger a perf buffer overflow when
tracing large scatter-gather lists. With devices like virtio-gpu
creating large DRM buffers, nents can exceed 1000 entries, resulting
in:
phys_addrs: 1000 * 8 bytes = 8,000 bytes
dma_addrs: 1000 * 8 bytes = 8,000 bytes
lengths: 1000 * 4 bytes = 4,000 bytes
Total: ~20,000 bytes
This exceeds PERF_MAX_TRACE_SIZE (8192 bytes), causing:
WARNING: CPU: 0 PID: 5497 at kernel/trace/trace_event_perf.c:405
perf buffer not large enough, wanted 24620, have 8192
Cap all three dynamic arrays at 128 entries using min() in the array
size calculation. This ensures arrays are only as large as needed
(up to the cap), avoiding unnecessary memory allocation for small
operations while preventing overflow for large ones.
The tracepoint now records the full nents/ents counts and a truncated
flag so users can see when data has been capped.
Changes in v2:
- Use min(nents, DMA_TRACE_MAX_ENTRIES) for dynamic array sizing
instead of fixed DMA_TRACE_MAX_ENTRIES allocation (feedback from
Steven Rostedt)
- This allocates only what's needed up to the cap, avoiding waste
for small operations
Reviwed-by: Sean Anderson <sean.anderson@linux.dev>
CVSS Score
7.8
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
netfilter: xt_CT: drop pending enqueued packets on template removal
Templates refer to objects that can go away while packets are sitting in
nfqueue refer to:
- helper, this can be an issue on module removal.
- timeout policy, nfnetlink_cttimeout might remove it.
The use of templates with zone and event cache filter are safe, since
this just copies values.
Flush these enqueued packets in case the template rule gets removed.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
netfilter: nf_tables: release flowtable after rcu grace period on error
Call synchronize_rcu() after unregistering the hooks from error path,
since a hook that already refers to this flowtable can be already
registered, exposing this flowtable to packet path and nfnetlink_hook
control plane.
This error path is rare, it should only happen by reaching the maximum
number hooks or by failing to set up to hardware offload, just call
synchronize_rcu().
There is a check for already used device hooks by different flowtable
that could result in EEXIST at this late stage. The hook parser can be
updated to perform this check earlier to this error path really becomes
rarely exercised.
Uncovered by KASAN reported as use-after-free from nfnetlink_hook path
when dumping hooks.
CVSS Score
7.8
EPSS Score
0.0
Published
2026-03-25
In the Linux kernel, the following vulnerability has been resolved:
tracing: Fix WARN_ON in tracing_buffers_mmap_close
When a process forks, the child process copies the parent's VMAs but the
user_mapped reference count is not incremented. As a result, when both the
parent and child processes exit, tracing_buffers_mmap_close() is called
twice. On the second call, user_mapped is already 0, causing the function to
return -ENODEV and triggering a WARN_ON.
Normally, this isn't an issue as the memory is mapped with VM_DONTCOPY set.
But this is only a hint, and the application can call
madvise(MADVISE_DOFORK) which resets the VM_DONTCOPY flag. When the
application does that, it can trigger this issue on fork.
Fix it by incrementing the user_mapped reference count without re-mapping
the pages in the VMA's open callback.
CVSS Score
5.5
EPSS Score
0.0
Published
2026-03-25