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CVE-2026-72406
net: sungem: fix probe error cleanup
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-2026-72406 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 | fixed | 6.1.180-1 | Update the kernel and reboot. Fixed in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.100-1 | Update the kernel and reboot. Fixed in 6.12.100-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.5-1 | Update the kernel and reboot. Fixed in 7.1.5-1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
gem_init_one() calls gem_remove_one() when register_netdev() fails. gem_remove_one() unregisters and frees resources owned by the net_device, including the DMA block, MMIO mapping, PCI regions, and the net_device itself. gem_init_one() then falls through to its own cleanup labels and frees the same resources again. Keep the register_netdev() error path in gem_init_one(): clear drvdata so PM/remove paths do not see a half-registered device, remove the NAPI instance added during probe, and let the existing cleanup labels release the resources once. The issue was found by a local static-analysis checker for probe error paths. The reported path was manually inspected before sending this fix. Compile-tested with CONFIG_SUNGEM=y. Runtime testing was not performed because no sungem hardware is available.
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/sun/sungem.c
- What this is
- NETWORKING DRIVERSMAINTAINERS section matched on drivers/net/ · netdev@vger.kernel.org · Maintained
- Kernel module
- sungem
Check it on the machine
grep -wE 'CONFIG_ETHERNET|CONFIG_NET_VENDOR_SUN|CONFIG_SUNGEM' /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 sungemPrints 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
- 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, 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, riscv64/riscv64, s390x/s390x
- M
- a module where it is built at all; some flavours do not build it
- Build switches
- CONFIG_ETHERNET, CONFIG_NET_VENDOR_SUN, CONFIG_SUNGEM
- 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
- 0.17%, higher than 5.8% 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 |
|---|---|---|
| 2.6.12 | 5.10.261 | f3bd60b26814 |
| 2.6.12 | 5.15.212 | f1d04fefb0c2 |
| 2.6.12 | 6.1.178 | 331c99029a1c |
| 2.6.12 | 6.6.145 | a63eaf7605d1 |
| 2.6.12 | 6.12.97 | fb73cdc50b67 |
| 2.6.12 | 6.18.40 | b15a3cc68e24 |
| 2.6.12 | 7.1.5 | bc49e8746584 |
| 2.6.12 | 7.2 | 36dea2f63924 |
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 flaw is in sungem PCI driver probe (gem_init_one) when register_netdev() fails during gem_init_one(); it is reached via local PCI enumeration/module load/hotplug/sysfs bind, not by processing remote network traffic through the NIC.
- AC:LAttack complexity, low
- An attacker can reliably force register_netdev() to fail with ENOMEM using memory exhaustion timed with sungem probe or reprobe (modprobe, PCI hotplug, or sysfs bind); no uncontrollable race or rare heap layout is required beyond attacker-driven pressure.
- PR:LPrivileges required, low
- Only a basic local process is needed to exhaust memory during probe; CAP_SYS_ADMIN/CAP_SYS_MODULE for driver rebind or modprobe is commonly available to maintenance operators, and concurrent unprivileged memory pressure can trigger the failing path without init-namespace root.
- UI:NUser interaction, none
- No victim interaction (opening files, mounting filesystems, clicking prompts) is required; exploitation is driven by attacker-timed memory pressure during sungem PCI probe error cleanup without actions from other users.
- S:UScope, unchanged
- The double-free corrupts kernel heap/DMA bookkeeping within the same kernel security domain; it enables local privilege escalation but does not cross VM, container, or IOMMU boundaries on its own.
- C:HConfidentiality impact, high
- gem_remove_one() followed by fallthrough cleanup double-frees dma_alloc_coherent memory and free_netdev(), and then dereferences freed netdev_priv(gp) in gem_put_cell/iounmap, giving UAF-class heap disclosure primitives.
- I:HIntegrity impact, high
- Repeated dma_free_coherent, pci_release_regions, and free_netdev on the same objects corrupts kernel heap/SLUB metadata and can be developed into arbitrary kernel writes or control-flow hijacking, not merely a one-time fault.
- A:HAvailability impact, high
- The double-free and subsequent use-after-free on probe error cleanup can immediately trigger kernel BUG/WARN, oops, or panic, causing total loss of system availability on affected legacy systems using sungem hardware.