Look up another CVE · open CVE-2026-93196 in the interactive tracker
CVE-2026-93196
nvdimm: virtio_pmem: refcount requests for token lifetime
Published 2026-09-17 (31 days ago) by the Linux kernel CNA. Subsystem drivers/nvdimm. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-93196 in every release this site tracks, and what each one means in practice. Every status below is the one the Debian Security Team publishes for this CVE. source
| Release | Status | Version | What this means |
|---|---|---|---|
| Debian 12bookworm | vulnerable | 6.1.190-1 | No fix published anywhere yet, neither in Debian nor upstream for the series bookworm tracks. Watch the Debian tracker page for this CVE. Advisories for bookworm have historically landed a median of 23 days after publication. |
| Debian 13trixie | fixedDSA-6568-1 · 2026-10-16 · text | 6.12.113-1 | Update the kernel and reboot. DSA-6568-1 shipped the fix on 2026-10-16, in 6.12.113-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.6-1 | Update the kernel and reboot. Fixed in 7.2.6-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
KASAN reports slab-use-after-free in __wake_up_common(): BUG: KASAN: slab-use-after-free in __wake_up_common+0x114/0x160 Read of size 8 at addr ffff88810fdcb710 by task swapper/0/0 CPU: 0 UID: 0 PID: 0 Comm: swapper/0 Not tainted 6.19.0-next-20260220-00006-g1eae5f204ec3 #4 PREEMPT(full) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Arch Linux 1.17.0-2-2 04/01/2014 Call Trace: <IRQ> dump_stack_lvl+0x6d/0xb0 print_report+0x170/0x4e2 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 ? __virt_addr_valid+0x1dc/0x380 kasan_report+0xbc/0xf0 ? __wake_up_common+0x114/0x160 ? __wake_up_common+0x114/0x160 __wake_up_common+0x114/0x160 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 __wake_up+0x36/0x60 virtio_pmem_host_ack+0x11d/0x3b0 ? sched_balance_domains+0x29f/0xb00 ? __pfx_virtio_pmem_host_ack+0x10/0x10 ? _raw_spin_lock_irqsave+0x98/0x100 ? __pfx__raw_spin_lock_irqsave+0x10/0x10 vring_interrupt+0x1c9/0x5e0 ? __pfx_vp_interrupt+0x10/0x10 vp_vring_interrupt+0x87/0x100 ? __pfx_vp_interrupt+0x10/0x10 __handle_irq_event_percpu+0x17f/0x550 ? __pfx__raw_spin_lock+0x10/0x10 handle_irq_event+0xab/0x1c0 handle_fasteoi_irq+0x276/0xae0 __common_interrupt+0x65/0x130 common_interrupt+0x78/0xa0 </IRQ> virtio_pmem_host_ack() wakes a request that has already been freed by the submitter. This happens when the request token is still reachable via the virtqueue, but virtio_pmem_flush() returns and frees it. Fix the token lifetime by refcounting struct virtio_pmem_request. virtio_pmem_flush() holds a submitter reference, and the virtqueue holds an extra reference once the request is queued. The completion path drops the virtqueue reference, and the submitter drops its reference before returning.
Where it lives
The fix touches these files. If the subsystem is one you do not use, the practical exposure is lower, though the package is still the vulnerable one.
drivers/nvdimm/nd_virtio.c
drivers/nvdimm/virtio_pmem.h
- What this is
- VIRTIO PMEM DRIVERMAINTAINERS section matched on drivers/nvdimm/nd_virtio.c · virtualization@lists.linux.dev · Maintained
- Kernel module
- nd_virtio
Check it on the machine
grep -wE 'CONFIG_LIBNVDIMM|CONFIG_VIRTIO_PMEM' /boot/config-$(uname -r)Reads the booted kernel's own configuration, on the machine and nowhere else. =y is built in, =m is a module, and an is not set line means the code is not there.
lsmod | grep -w nd_virtioPrints a line if that module is loaded right now, and nothing if it is not. One that is not loaded can still be loaded later by anything that needs it.
Show whether Debian builds this, per release
Debian builds this, but not on every flavour. At least one release below builds the code on some of its kernel flavours and not on others, so the answer depends on the architecture and flavour installed.
- bookwormMnot built on armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, i386/686, ppc64el/powerpc64le
- trixieMnot built on armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, s390x/s390x
- forky, sidMnot built on armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, s390x/s390x
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_LIBNVDIMM, CONFIG_VIRTIO_PMEM
- Reads as
- all on means the file is compiled; any one off means it is not.
From the configuration Debian publishes for every kernel flavour it builds. It covers only the architectures Debian ships a linux-config package for, and nothing about a kernel you built yourself. Debian's own status above stays authoritative about the source package.MAINTAINERS kbuild Makefiles Debian linux-config packages
Signals
- Published
- 2026-09-17 (31 days ago)source
- CVSS
- 8.4 high
CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.19%, higher than 8.1% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/nvdimm
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.3 | 6.12.112 | 4691c137e9cb |
| 5.3 | 6.18.52 | be072a5d5e35 |
| 5.3 | 7.2.6 | b1e740b91566 |
| 5.3 | 7.3 | e57140944b5a |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DSA-6568-1 | 2026-10-16 | trixie 6.12.113-1 | tracker |
Why the CNA scored it this way
Quoted from the kernel CNA's own scoring file, word for word. A highlighted metric carries the most severe value CVSS v3.1 defines for it, which is what pushes the score up. source
- AV:LAttack vector, local
- 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.
- AC:LAttack complexity, low
- 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.
- PR:NPrivileges required, none
- virtio_pmem_host_ack() authenticates nothing and holds no guest credential. Host-initiated unplug runs virtio_pmem_remove()→nvdimm_bus_unregister()→nd_pmem_remove(), which calls nvdimm_flush(nd_region, NULL)→virtio_pmem_flush() with no capable() check before the token is queued on req_vq.
- UI:NUser interaction, none
- 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.
- S:UScope, unchanged
- 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.
- C:HConfidentiality impact, high
- 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.
- I:HIntegrity impact, high
- 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.
- A:HAvailability impact, high
- 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.