v1.15.1

**Fixed**

* [#5762](https://github.com/firecracker-microvm/firecracker/pull/5762): Cap virtio-rng per-request entropy to 64 KiB. Previously, a guest could construct a descriptor chain that caused Firecracker to allocate more host memory than the guest actually provided, potentially leading to excessive host memory consumption.
* [#5818](https://github.com/firecracker-microvm/firecracker/pull/5818): Enforce the virtio device initialization sequence in the PCI transport, matching the existing MMIO transport behavior. The PCI transport now validates device status transitions, rejects queue configuration writes outside the FEATURES_OK to DRIVER_OK window, rejects feature negotiation outside the DRIVER state, blocks re-initialization after a failed reset, and sets DEVICE_NEEDS_RESET when device activation fails. This fixes [CVE-2026-5747](https://www.cve.org/CVERecord?id=CVE-2026-5747).
* [#5818](https://github.com/firecracker-microvm/firecracker/pull/5818): Reject device status writes that clear previously set bits in the MMIO transport, except for reset.
* [#5780](https://github.com/firecracker-microvm/firecracker/pull/5780): Fixed missing `/sys/devices/system/cpu/cpu*/cache/*` in aarch64 guests when running on host kernels >= 6.3 with guest kernels >= 6.1.156.
* [#5793](https://github.com/firecracker-microvm/firecracker/pull/5793): Fixed virtio-mem plug/unplug skipping KVM slot updates for memory blocks not aligned to a slot boundary. On plug, this could leave hotplugged memory inaccessible to the guest. On unplug, the guest could retain access to memory that Firecracker considered freed.
* [#5794](https://github.com/firecracker-microvm/firecracker/pull/5794): Bound balloon statistics descriptor length to prevent a guest-controlled oversized descriptor from temporarily stalling the VMM event loop. Only affects microVMs with `stats_polling_interval_s > 0`.
* [#5809](https://github.com/firecracker-microvm/firecracker/pull/5809): Fixed a bug on host Linux >= 5.16 for x86_64 guests using the `kvm-clock` clock source causing the monotonic clock to jump on restore by the wall-clock time elapsed since the snapshot was taken. Users using `kvm-clock` that want to explicitly advance the clock with `KVM_CLOCK_REALTIME` can opt back in using the new `clock_realtime` flag in `LoadSnapshot` API.