Look up another CVE · open CVE-2026-97990 in the interactive tracker
CVE-2026-97990
vdpa_sim_net: check TX pull result before RX copy
Published 2026-09-25 (24 days ago) by the Linux kernel CNA. Subsystem drivers/vdpa. Debian urgency: not yet assigned.
Debian does not build this code. The per-release build detail is under "Where it lives" below.
What to do, per Debian release
Debian's own status for CVE-2026-97990 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-6528-1 · 2026-09-29 · text | 6.12.111-1 | Update the kernel and reboot. DSA-6528-1 shipped the fix on 2026-09-29, in 6.12.111-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.2.7-1 | Update the kernel and reboot. Fixed in 7.2.7-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.2.7-1 | Update the kernel and reboot. Fixed in 7.2.7-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4817-1 · 2026-10-04 · text | 6.12.111-1~deb12u1 | Update the kernel and reboot. DLA-4817-1 shipped the fix on 2026-10-04, in 6.12.111-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
vringh_iov_pull_iotlb() returns a signed byte count. A failed TX pull is currently added to the unsigned byte counter and then passed as a size_t length to receive_filter() and vringh_iov_push_iotlb(). A negative error can therefore become a large length in the RX path. Handle non-positive pull results before every length use. Count the TX error and complete the consumed TX descriptor with zero bytes. I found this bug myself, though the patch was written with AI assistance.
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/vdpa/vdpa_sim/vdpa_sim_net.c
- What this is
- VIRTIO COREMAINTAINERS section matched on drivers/vdpa/ · virtualization@lists.linux.dev · Maintained
- Kernel module
- none to look for. The file would have gone into vdpa_sim_net, and Debian does not compile it into that module, so finding vdpa_sim_net in lsmod would say nothing about this CVE.
Check it on the machine
grep -wE 'CONFIG_VDPA|CONFIG_VDPA_SIM|CONFIG_VDPA_SIM_NET' /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.
Show whether Debian builds this, per release
Debian does not build this code. In 5 releases below, every kernel flavour Debian publishes has the switch off, so the vulnerable file is compiled into no kernel binary Debian ships.
- bookworm, trixie, forky, sid, bookworm · linux-6.12n
- n
- not enabled on any flavour - this release does not build the code
- Build switches
- CONFIG_VDPA, CONFIG_VDPA_SIM, CONFIG_VDPA_SIM_NET
- 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
- 2026-09-25 (24 days ago)source
- CVSS
- 7.5 high
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.12%, higher than 1.6% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/vdpa
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.19 | 6.6.158 | 1b803d382cde |
| 5.19 | 6.12.111 | c001abcde865 |
| 5.19 | 6.18.53 | 3af20238a09c |
| 5.19 | 7.2.7 | 2bbf1c1f6999 |
| 5.19 | 7.3 | 0d195797a80b |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4817-1 | 2026-10-04 | bookworm 6.12.111-1~deb12u1 | tracker |
| DSA-6528-1 | 2026-09-29 | trixie 6.12.111-1 | 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
- The malformed input is a virtqueue TX descriptor with an unmapped address, written into the vring by whoever drives the vdpa_sim_net device (a guest via vhost-vdpa or a local vhost-vdpa user). vdpasim_net_work() processes it and no network protocol carries it.
- AC:HAttack complexity, high
- Once reached, the failed vringh_iov_pull_iotlb() is deterministic. But it requires an admin to create a vdpa_sim_net device (a test-only simulator under RUNTIME_TESTING_MENU) and assign it to the attacker's VM or process, a configuration the attacker cannot produce.
- PR:LPrivileges required, low
- Device creation needs GENL_ADMIN_PERM in init_net (not reachable via user namespaces). The attacker is the guest or process given the device, which only needs ordinary control of its own virtqueues and no host privileges.
- UI:NUser interaction, none
- The attacker queues a broadcast TX frame, then a TX descriptor that fails IOTLB translation, plus large RX descriptors, all on their own rings. No victim action is needed.
- S:CScope, changed
- A guest driving vdpa_sim_net through vhost-vdpa causes the host kernel to copy host heap memory into guest-visible RX buffers, crossing the VM-to-host boundary.
- C:HConfidentiality impact, high
- The negative read, cast to size_t, is passed to vringh_iov_push_iotlb(). It copies from the PAGE_SIZE net->buffer up to the attacker-sized RX iov, leaking adjacent host kernel heap (an out-of-bounds read not limited to a few bytes) into attacker memory.
- I:NIntegrity impact, none
- The overlong copy only reads kernel memory and writes into the attacker's own RX buffers; no kernel memory is written. The only other effect is corrupted tx_bytes statistics.
- A:HAvailability impact, high
- A large RX descriptor chain makes the out-of-bounds read of net->buffer run into unmapped memory, oopsing the host kernel and taking down every guest on it.