Security Vulnerabilities
In the Linux kernel, the following vulnerability has been resolved:
KVM: x86: Ensure vendor's exit handler runs before fastpath userspace exits
Move the handling of fastpath userspace exits into vendor code to ensure
KVM runs vendor specific operations that need to run before userspace gains
control of the vCPU. E.g. for VMX (and soon to be for SVM as well), KVM
needs to flush the PML buffer prior to exiting to userspace, otherwise any
memory written by the final KVM_RUN might never be flagged as dirty.
Note, waiting to snapshot CR0 and CR3 until svm_handle_exit() is flawed in
general, as that risks consuming stale state in a fastpath handler. That
will be addressed in a future change.
CVSS Score
7.1
EPSS Score
0.001
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
KVM: SEV: Pin source page for write when adding CPUID data for SNP guest
When populating a guest_memfd instance with the initial CPUID data for an
SNP guest, acquire a writable pin on the source page as KVM will write back
the "correct" CPUID information if the userspace provided data is rejected
by trusted firmware. Because KVM writes to the source page using a kernel
mapping, pinning for read could result in KVM clobbering read-only memory.
Note, well-behaved VMMs are unlikely to be affected, as CPUID information
is almost always dynamically generated by userspace, i.e. it's unlikely for
the CPUID information to be backed by a read-only mapping.
[sean: rewrite shortlog and changelog, tag for stable@]
CVSS Score
5.5
EPSS Score
0.001
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Clear __hyp_running_vcpu when flushing the pKVM hyp vCPU
flush_hyp_vcpu() copies the host vCPU context into the hyp's private
vCPU on every run. ctxt_to_vcpu() expects a guest context to have a
NULL __hyp_running_vcpu, which is only ever set on the host context, so
that it resolves the vCPU via container_of(). While this is generally
the case, flush_hyp_vcpu() copies the context verbatim and does not
enforce this, so a value provided by the host is dereferenced at EL2
(host -> EL2).
Fix by clearing __hyp_running_vcpu after the copy.
CVSS Score
8.2
EPSS Score
0.002
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: Bound used_lrs when flushing the pKVM hyp vCPU
flush_hyp_vcpu() copies the host vGIC state into the hyp's private vCPU
on every run. The vGIC list register save and restore use used_lrs as
their loop bound and expect it to stay within the number of implemented
list registers. While this is generally the case, flush_hyp_vcpu()
copies vgic_v3 verbatim and does not enforce this, so a value provided
by the host is used at EL2 to index vgic_lr[] and access ICH_LR<n>_EL2
(host -> EL2).
Fix by clamping used_lrs to the number of implemented list registers
after the copy, as the trusted path already does in
vgic_flush_lr_state(). The number of implemented list registers is
constant after init, so it is replicated once from
kvm_vgic_global_state.nr_lr into hyp_gicv3_nr_lr rather than read on
every entry.
CVSS Score
8.2
EPSS Score
0.002
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
KVM: arm64: nv: Avoid dereferencing NULL VNCR pseudo-TLB
VNCR TLB invalidation occurs from MMU notifiers or TLBI instructions,
and either can race against a vcpu not being onlined yet (no pseudo-TLB
allocated). Similarly, the TLB might be invalid, and the invalidation
should be skipped in this case.
Both kvm_invalidate_vncr_ipa() and kvm_invalidate_vncr_va() are
expected to perform the same checks, except that the latter doesn't
check for the allocation and blindly dereferences the pointer.
Solve this by introducing a new iterator built on top of the usual
kvm_for_each_vcpu() that checks for both of the above conditions,
and convert the two users to it.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
iommufd: Set upper bounds on cache invalidation entry_num and entry_len
iommufd_hwpt_invalidate() takes a user-controlled entry_num and entry_len,
each bounded only by U32_MAX. An entry_len beyond the kernel's struct size
makes the copy helper verify the extra bytes are zero, scanning that excess
in one uninterruptible pass; a multi-gigabyte value over zeroed user memory
trips the soft-lockup watchdog.
A large entry_num is the other half, driving the backend invalidation loop
with no reschedule. The VT-d nested handler, for one, copies each entry and
flushes caches per iteration, pinning the CPU on a non-preemptible kernel.
Cap both in the ioctl. entry_len is held under PAGE_SIZE, above any request
struct, and entry_num under 1 << 19, the order of a hardware invalidation
queue and well beyond any real batch, bounding the per-call loop length.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
iommufd: Break the loop on failure in iommufd_fault_fops_read()
On a copy_to_user() failure inside the inner list_for_each_entry, only the
inner loop breaks; the outer while re-fetches the just-restored fault group
and retries the failing copy_to_user() forever, spinning the reader at 100%
CPU with fault->mutex held.
Check rc after the inner loop and break the outer while as well.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
iommufd: Set veventq_depth upper bound
iommufd_veventq_alloc() accepts any !0 veventq_depth from userspace, with
an upper bound at U32_MAX.
This leaves a vulnerability where userspace can allocate excessively large
queues to exhaust kernel memory reserves.
Cap the veventq_depth (maximum number of entries) to 1 << 19, matching the
maximum number of entries in the SMMUv3 EVTQ (the largest use case today).
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
iommufd: Move vevent memory allocation outside spinlock
The veventq memory allocation happens inside the spinlock. Given its depth
is decided by the user space, this leaves a vulnerability, where userspace
can allocate large queues to exhaust atomic memory reserves.
Move the allocation outside the spinlock and use GFP_NOWAIT, which can fail
fast under memory pressure without dipping into the GFP_ATOMIC reserves or
direct-reclaiming from the threaded IRQ handler. On allocation failure,
queue the lost_events_header (so userspace learns of the drop) and return
-ENOMEM so the caller learns of the kernel-side memory pressure.
This is intentionally distinct from the queue-overflow path, which also
queues the lost_events_header but returns 0: a full queue is an expected
userspace-pacing condition rather than a kernel error.
A subsequent change will cap the upper bound of the veventq_depth.
CVSS Score
5.5
EPSS Score
0.002
Published
2026-07-25
In the Linux kernel, the following vulnerability has been resolved:
Input: synaptics-rmi4 - bound the F30 keymap to the GPIO/LED count
rmi_f30_map_gpios() allocates gpioled_key_map with
min(gpioled_count, TRACKSTICK_RANGE_END) == at most 6 entries, but
rmi_f30_attention() iterates the full f30->gpioled_count (device query
register, range 0..31) and dereferences gpioled_key_map[i], and
input->keycodemax is set to the full gpioled_count while input->keycode
points at the 6-entry allocation.
A device that reports gpioled_count > 6 with GPIO support enabled
therefore causes an out-of-bounds read on the attention interrupt and
out-of-bounds read/write through the EVIOCGKEYCODE/EVIOCSKEYCODE ioctls,
which bound the index only against keycodemax. This is the same defect
as the F3A handler, which was copied from F30.
Size the keymap for the full gpioled_count; the mapping loop still
assigns only the first min(gpioled_count, TRACKSTICK_RANGE_END) entries.
CVSS Score
7.8
EPSS Score
0.002
Published
2026-07-25