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CVE-2026-64279
i2c: core: fix adapter deregistration race
Published 2026-07-25 (3 months ago) by the Linux kernel CNA. Subsystem drivers/i2c. Debian urgency: not yet assigned.
What to do, per Debian release
Debian's own status for CVE-2026-64279 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-4720-1 · 2026-08-05 · text | 6.1.180-1 | Update the kernel and reboot. DLA-4720-1 shipped the fix on 2026-08-05, in 6.1.180-1. A running kernel keeps the old code until the machine restarts. |
| Debian 13trixie | fixed | 6.12.96-1 | Update the kernel and reboot. Fixed in 6.12.96-1. A running kernel keeps the old code until the machine restarts. |
| Debian 14forky | fixed | 7.1.4-1 | Update the kernel and reboot. Fixed in 7.1.4-1. A running kernel keeps the old code until the machine restarts. |
| Debian unstablesid | fixed | 7.1.4-1 | Update the kernel and reboot. Fixed in 7.1.4-1. A running kernel keeps the old code until the machine restarts. |
| Debian 12bookworm · linux-6.12 | fixedDLA-4724-1 · 2026-08-07 · text | 6.12.100-1~deb12u1 | Update the kernel and reboot. DLA-4724-1 shipped the fix on 2026-08-07, in 6.12.100-1~deb12u1. A running kernel keeps the old code until the machine restarts. |
The vulnerability
What the bug is
Adapters can be looked up by their id using i2c_get_adapter() which takes a reference to the embedded struct device. Remove the adapter from the IDR before tearing it down during deregistration (and on registration failure) to make sure its resources are not accessed after having been freed (e.g. the device name).
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/i2c/i2c-core-base.c
- What this is
- I2C SUBSYSTEMMAINTAINERS section matched on drivers/i2c/* · linux-i2c@vger.kernel.org · Maintained
- Kernel module
- i2c_core
Check it on the machine
grep -w CONFIG_I2C /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 i2c_corePrints 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.
- bookwormYnot built on amd64/cloud-amd64, arm64/cloud-arm64
- trixie, forky, sidBnot built on amd64/cloud-amd64, arm64/cloud-arm64
- bookworm · linux-6.12Ynot built on amd64/cloud-amd64, arm64/cloud-arm64
- Y
- built in where it is built at all; some flavours do not build it
- B
- built in on some, a module on others, absent on the rest
- Build switch
- CONFIG_I2C
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
- 2026-07-25 (3 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 2.5% of all CVEssource
- CISA KEV
- not listedthe KEV catalogue
- Debian urgency
- not yet assignedsource
- Subsystem
- drivers/i2c
Upstream fixes
The versions the CNA records as introducing and fixing this, and the commit for each. source
| Introduced | Fixed in | Commit |
|---|---|---|
| 2.6.31 | 5.15.212 | d39282f552dd |
| 2.6.31 | 6.1.178 | 11dfa37bf544 |
| 2.6.31 | 6.6.145 | 9882a9bd74db |
| 2.6.31 | 6.12.96 | bb234487a447 |
| 2.6.31 | 6.18.39 | b6d2af6fe9c1 |
| 2.6.31 | 7.1.4 | 35dbd1f1f603 |
| 2.6.31 | 7.2 | b1a58ed9eab1 |
Debian advisories
| Advisory | Date | Shipped to | Debian |
|---|---|---|---|
| DLA-4724-1 | 2026-08-07 | bookworm 6.12.100-1~deb12u1 | tracker |
| DLA-4723-1 | 2026-08-07 | bullseye 6.1.180-1~deb11u1 | tracker |
| DLA-4720-1 | 2026-08-05 | bookworm 6.1.180-1 | 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
- An attacker reaches the vulnerable lookup through local open/openat calls on /dev/i2c-N and can trigger dynamic-adapter teardown through local usbfs ioctls. No network path directly reaches i2c_get_adapter().
- AC:LAttack complexity, low
- An attacker with access to both device nodes can control both sides by racing parallel I2C opens against repeatable USBDEVFS_DISCONNECT and rebind operations. No victim-controlled timing or uncontrollable condition is required.
- PR:LPrivileges required, low
- i2cdev_open() and the usbfs disconnect path impose device-node DAC, LSM, and device-cgroup checks but no capability requirement. A regular user granted I2C and USB-device access can trigger the race without init-namespace root.
- UI:NUser interaction, none
- The attacker can initiate the adapter lookup, software disconnect, and subsequent stale-adapter operations directly. No separate victim action is required.
- S:UScope, unchanged
- Exploitation corrupts or executes code within the same host kernel security authority. This is ordinary local kernel privilege escalation rather than a VM, IOMMU, or other scope-boundary escape.
- C:HConfidentiality impact, high
- The race can return an adapter after its embedded device resources have been released, followed by freeing of the enclosing dynamic-adapter allocation. Reclaiming this heap object permits attacker-influenced pointer dereferences and potential arbitrary kernel-memory disclosure.
- I:HIntegrity impact, high
- The stale adapter contains algorithm and locking function pointers, while I2C ioctls also write mutable adapter fields. Heap reclamation can therefore provide memory-corruption and control-flow-hijacking primitives leading to kernel code execution.
- A:HAvailability impact, high
- Refcount resurrection, stale device-resource accesses, and dereferences through a freed adapter can produce kernel warnings, oopses, or panics. An attacker controlling disconnect and rebind can repeat the trigger.