{ "schema_version": "1.6.1", "id": "RPI-CVE-2026-93196", "modified": "2026-10-09T11:39:44Z", "upstream": [ "CVE-2026-93196" ], "published": "2026-09-17T16:10:40Z", "summary": "nvdimm: virtio_pmem: refcount requests for token lifetime", "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnvdimm: virtio_pmem: refcount requests for token lifetime\n\nKASAN reports slab-use-after-free in __wake_up_common():\nBUG: KASAN: slab-use-after-free in __wake_up_common+0x114/0x160\nRead of size 8 at addr ffff88810fdcb710 by task swapper/0/0\n\nCPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted\n6.19.0-next-20260220-00006-g1eae5f204ec3 #4 PREEMPT(full)\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux\n1.17.0-2-2 04/01/2014\nCall Trace:\n \n dump_stack_lvl+0x6d/0xb0\n print_report+0x170/0x4e2\n ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n ? __virt_addr_valid+0x1dc/0x380\n kasan_report+0xbc/0xf0\n ? __wake_up_common+0x114/0x160\n ? __wake_up_common+0x114/0x160\n __wake_up_common+0x114/0x160\n ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n __wake_up+0x36/0x60\n virtio_pmem_host_ack+0x11d/0x3b0\n ? sched_balance_domains+0x29f/0xb00\n ? __pfx_virtio_pmem_host_ack+0x10/0x10\n ? _raw_spin_lock_irqsave+0x98/0x100\n ? __pfx__raw_spin_lock_irqsave+0x10/0x10\n vring_interrupt+0x1c9/0x5e0\n ? __pfx_vp_interrupt+0x10/0x10\n vp_vring_interrupt+0x87/0x100\n ? __pfx_vp_interrupt+0x10/0x10\n __handle_irq_event_percpu+0x17f/0x550\n ? __pfx__raw_spin_lock+0x10/0x10\n handle_irq_event+0xab/0x1c0\n handle_fasteoi_irq+0x276/0xae0\n __common_interrupt+0x65/0x130\n common_interrupt+0x78/0xa0\n \n\nvirtio_pmem_host_ack() wakes a request that has already been freed by the\nsubmitter.\n\nThis happens when the request token is still reachable via the virtqueue,\nbut virtio_pmem_flush() returns and frees it.\n\nFix the token lifetime by refcounting struct virtio_pmem_request.\nvirtio_pmem_flush() holds a submitter reference, and the virtqueue holds an\nextra reference once the request is queued. The completion path drops the\nvirtqueue reference, and the submitter drops its reference before\nreturning.", "severity": [ { "type": "CVSS_V3", "score": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H" } ], "affected": [ { "package": { "ecosystem": "Raspberry Pi OS:12", "name": "linux" }, "versions": [ "1:6.1.47-1+rpt4" ], "ecosystem_specific": { "binaries": [ { "binary_name": "linux-image-6.1.0-rpi3-rpi-2712", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v6", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v7l", "binary_version": "1:6.1.47-1+rpt4" }, { "binary_name": "linux-image-6.1.0-rpi3-rpi-v8", "binary_version": "1:6.1.47-1+rpt4" } ] }, "database_specific": { "per_version": { "1:6.1.47-1+rpt4": { "linux_commit": "655fc658a15ae7a6f37103754adb39ba52a9a14e", "upstream_version": "6.1.47", "assessment": "commit ancestry (strak rule)", "upstream_fixed": null, "compiled_filter": false } } } } ], "references": [ { "type": "ADVISORY", "url": "https://www.cve.org/CVERecord?id=CVE-2026-93196" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/4691c137e9cbe76137d730a26d663d900ac7279b" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/be072a5d5e35f4bdf2da22f600b5d6dc6c5ff491" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/b1e740b9156621afd4c4aa66257f4dde8df1febe" }, { "type": "FIX", "url": "https://git.kernel.org/stable/c/e57140944b5a47a7fd5a142faab29a02af040bc8" } ], "database_specific": { "source": "https://git.kernel.org/pub/scm/linux/security/vulns.git", "upstream_modified": "2026-10-03T11:04:09Z", "severity": { "source": "kernel CNA", "cvss_v3_score": 8.4, "cvss_v3_severity": "High", "scenario": "AV:L - virtio_pmem_host_ack() is the flush_queue callback registered in init_vq() and invoked from vring_interrupt() when the virtio-pmem backend completes a token; pmem_submit_bio() (REQ_PREFLUSH/REQ_FUA) and nd_pmem_remove() reach virtio_pmem_flush() only on that paravirtual device, not via a routable protocol message.\nAC:L - virtio_pmem_flush() kfree()s req_data after virtqueue_kick() fails while the token remains in req_vq, and on the success path kfree()s it while virtio_pmem_host_ack() still runs wake_up(&req_data->host_acked); a backend writing the used ring, or concurrent PREFLUSH/FUA bios (flush_lock only exists after a9ba6733), drives that lifetime hole.\nPR:N - virtio_pmem_host_ack() authenticates nothing and holds no guest credential. Host-initiated unplug runs virtio_pmem_remove()\u2192nvdimm_bus_unregister()\u2192nd_pmem_remove(), which calls nvdimm_flush(nd_region, NULL)\u2192virtio_pmem_flush() with no capable() check before the token is queued on req_vq.\nUI:N - nd_pmem_remove()/nd_pmem_shutdown() submit virtio_pmem_flush() during teardown the backend/VMM initiates, and virtio_pmem_host_ack() then runs from vring_interrupt with no guest ioctl, mount, or file open; a local user of /dev/pmem likewise issues their own PREFLUSH/FUA bios.\nS:U - The freed object is a guest kmalloc struct virtio_pmem_request used only inside virtio_pmem_flush() and virtio_pmem_host_ack(); corruption stays in that guest kernel and is not a KVM/Xen guest-to-host escape or IOMMU/DMA bypass.\nC:H - virtio_pmem_host_ack() takes the freed token from virtqueue_get_buf() and writes req_data->done then wake_up(&req_data->host_acked) on the kfree'd slab; reuse of that virtio_pmem_request is a use-after-free read primitive once the object is sprayed.\nI:H - KASAN reports slab-use-after-free in __wake_up_common() from virtio_pmem_host_ack(): wake_up() walks the freed host_acked wait_queue_head, so a sprayed wait_queue_entry.func yields an indirect call and list-pointer write.\nA:H - KASAN reports slab-use-after-free in __wake_up_common() from virtio_pmem_host_ack() in vring_interrupt IRQ context on swapper/0, which oopses or panics the guest even when the UAF is not turned into a full exploit." } } }