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CVE-2026-74548
forcedeth: fix UAF of txrx_stats in nv_remove
Published 2026-08-15 (2 months ago) by the Linux kernel CNA. Subsystem drivers/net. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-74548 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 | fixedDLA-4777-1 · 2026-09-08 · text | 6.1.187-1 | Update the kernel and reboot. DLA-4777-1 shipped the fix on 2026-09-08, in 6.1.187-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixedDSA-6466-1 · 2026-08-25 · text | 6.12.105-1 | Update the kernel and reboot. DSA-6466-1 shipped the fix on 2026-08-25, in 6.12.105-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.8-1 | Update the kernel and reboot. Fixed in 7.1.8-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4788-1 · 2026-09-19 · text | 6.12.107-1~deb12u1 | Update the kernel and reboot. DLA-4788-1 shipped the fix on 2026-09-19, in 6.12.107-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
nv_remove() frees the per-CPU txrx_stats before unregister_netdev(). Until unregister completes, ndo_get_stats64, the NAPI/xmit data path, and nv_close()/drain may still access txrx_stats, leading to a use-after-free. Free the stats only after unregister_netdev().
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/net/ethernet/nvidia/forcedeth.c
- What this is
- FORCEDETH GIGABIT ETHERNET DRIVERMAINTAINERS section matched on drivers/net/ethernet/nvidia/* · netdev@vger.kernel.org · Maintained
- Kernel module
- forcedeth
Check it on the machine
grep -wE 'CONFIG_ETHERNET|CONFIG_FORCEDETH|CONFIG_NET_VENDOR_NVIDIA' /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 forcedethPrints 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 amd64/cloud-amd64, arm64/arm64, arm64/cloud-arm64, arm64/rt/arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le
- trixieMnot built on amd64/cloud-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armel/rpi, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- forky, sidMnot built on amd64/cloud-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt-arm64, armhf/armmp, armhf/armmp-lpae, loong64/loong64, ppc64el/powerpc64le, ppc64el/powerpc64le-64k, riscv64/riscv64, s390x/s390x
- bookworm · linux-6.12Mnot built on amd64/cloud-amd64, arm64/arm64, arm64/arm64-16k, arm64/cloud-arm64, arm64/rt/arm64, armhf/armmp, armhf/armmp-lpae, armhf/rt/armmp, ppc64el/powerpc64le, ppc64el/powerpc64le-64k
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_ETHERNET, CONFIG_FORCEDETH, CONFIG_NET_VENDOR_NVIDIA
- 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
- 2026-08-15 (2 months ago)source
- CVSS
- 7.8 high
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hsource recompute it - Attack vector
- local (AV:L)source
- EPSS
- 0.13%, higher than 2.0% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/net
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 5.3 | 5.10.265 | cdf864d5d3c8 |
| 5.3 | 5.15.216 | 7c22b4ee0bd0 |
| 5.3 | 6.1.183 | d51ce7a63b76 |
| 5.3 | 6.6.151 | cf2dcde22845 |
| 5.3 | 6.12.103 | c9d24a205fd5 |
| 5.3 | 6.18.44 | ae20a8a4de06 |
| 5.3 | 7.1.8 | 201e05aa531e |
| 5.3 | 7.2 | 22666ba14201 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4788-1 | 2026-09-19 | bookworm 6.12.107-1~deb12u1 | tracker |
| DLA-4777-1 | 2026-09-08 | bookworm 6.1.187-1 | tracker |
| DSA-6466-1 | 2026-08-25 | trixie 6.12.105-1 | 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 UAF is opened in nv_remove() during local PCI/driver teardown (sysfs unbind, module unload, or hot-unplug); although NAPI/xmit and stats readers can run concurrently on still-registered netdev traffic, there is no standalone remote path into nv_remove itself.
- AC:LAttack complexity, low
- Once teardown starts, unregister_netdev() deterministically calls nv_close()→nv_drain_tx(), which increments freed txrx_stats when TX skbs remain, and an attacker can also drive the race by timing unbind against stats polling or packet I/O they control.
- PR:LPrivileges required, low
- Privileged teardown opens the window, but unprivileged peers can supply the concurrent netdev access (rtnetlink/sysfs stats via nv_get_stats64, and RX/TX on the still-up interface) that performs the UAF; per CNA driver-removal UAF precedent and the higher-severity tiebreak, PR:L.
- UI:NUser interaction, none
- No separate victim action is required beyond routine driver removal or module unload on a live interface; monitoring daemons and network traffic can hit the freed stats automatically during the unregister window without user cooperation.
- S:UScope, unchanged
- Impact is kernel heap corruption and crash/privilege escalation within the host kernel security authority; it does not cross VM, hypervisor, IOMMU, or container sandbox boundaries.
- C:HConfidentiality impact, high
- The bug is a kmalloc-backed per-CPU UAF: nv_get_stats64 reads freed nv_txrx_stats counters via per_cpu_ptr(), and once the slab is reallocated an attacker can obtain arbitrary kernel memory disclosure.
- I:HIntegrity impact, high
- Freed txrx_stats are updated from NAPI/xmit and nv_drain_tx() via __this_cpu_inc/add on attacker-influenced traffic, enabling heap grooming and controlled writes through the dangling per-CPU pointer for code execution.
- A:HAvailability impact, high
- Use-after-free dereferences of txrx_stats during netdev teardown reliably cause kernel oops/panic (as in the fix description), and even unsuccessful exploitation still crashes the system when concurrent RX/TX or drain paths touch freed memory.