# CVE-2022-49900: i2c: piix4: Fix adapter not be removed in piix4_remove()

> A use-after-free vulnerability in the Linux kernel's i2c piix4 driver allows attackers to cause a system crash or potentially execute code via module removal.

- **Severity:** High 7.8 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 1 May 2025
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2022-49900, GHSA-h3mh-rq8w-j65m, UBUNTU-CVE-2022-49900

## What is CVE-2022-49900?

CVE-2022-49900 is a high-severity use after free vulnerability in Linux kernel, published on 1 May 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

i2c: piix4: Fix adapter not be removed in piix4_remove()

In piix4_probe(), the piix4 adapter will be registered in:

   piix4_probe()
     piix4_add_adapters_sb800() / piix4_add_adapter()
       i2c_add_adapter()

Based on the probed device type, piix4_add_adapters_sb800() or single
piix4_add_adapter() will be called.
For the former case, piix4_adapter_count is set as the number of adapters,
while for antoher case it is not set and kept default *zero*.

When piix4 is removed, piix4_remove() removes the adapters added in
piix4_probe(), basing on the piix4_adapter_count value.
Because the count is zero for the single adapter case, the adapter won't
be removed and makes the sources allocated for adapter leaked, such as
the i2c client and device.

These sources can still be accessed by i2c or bus and cause problems.
An easily reproduced case is that if a new adapter is registered, i2c
will get the leaked adapter and try to call smbus_algorithm, which was
already freed:

Triggered by: rmmod i2c_piix4 && modprobe max31730

 BUG: unable to handle page fault for address: ffffffffc053d860
 #PF: supervisor read access in kernel mode
 #PF: error_code(0x0000) - not-present page
 Oops: 0000 [#1] PREEMPT SMP KASAN
 CPU: 0 PID: 3752 Comm: modprobe Tainted: G
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996)
 RIP: 0010:i2c_default_probe (drivers/i2c/i2c-core-base.c:2259) i2c_core
 RSP: 0018:ffff888107477710 EFLAGS: 00000246
 ...
 <TASK>
  i2c_detect (drivers/i2c/i2c-core-base.c:2302) i2c_core
  __process_new_driver (drivers/i2c/i2c-core-base.c:1336) i2c_core
  bus_for_each_dev (drivers/base/bus.c:301)
  i2c_for_each_dev (drivers/i2c/i2c-core-base.c:1823) i2c_core
  i2c_register_driver (drivers/i2c/i2c-core-base.c:1861) i2c_core
  do_one_initcall (init/main.c:1296)
  do_init_module (kernel/module/main.c:2455)
  ...
 </TASK>
 ---[ end trace 0000000000000000 ]---

Fix this problem by correctly set piix4_adapter_count as 1 for the
single adapter so it can be normally removed.

Weakness: CWE-415 (Double Free)

## Which versions are affected by CVE-2022-49900?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-49900?

Apply the vendor's patch.

## Is CVE-2022-49900 being exploited?

There is no known exploitation of CVE-2022-49900 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2022-49900 and fix it if it is affected.

What it is: CVE-2022-49900 is a high-severity use after free vulnerability in Linux kernel, published on 1 May 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2022-49900 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2022-49900/ (Markdown: https://insights.sbomify.com/CVE-2022-49900/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-49900
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-49900
- OSV: https://osv.dev/vulnerability/CVE-2022-49900

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-49900/
Summaries are generated and may contain mistakes; the official description above is the record.