# CVE-2022-48953: rtc: cmos: Fix event handler registration ordering issue

> A NULL pointer dereference in the Linux kernel RTC CMOS driver can cause a system crash during boot if an RTC event is active.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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:** 21 Oct 2024
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2022-48953, GHSA-8j4x-47rq-vf32, UBUNTU-CVE-2022-48953

## What is CVE-2022-48953?

CVE-2022-48953 is a medium-severity vulnerability in Linux kernel, published on 21 Oct 2024. 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:

rtc: cmos: Fix event handler registration ordering issue

Because acpi_install_fixed_event_handler() enables the event
automatically on success, it is incorrect to call it before the
handler routine passed to it is ready to handle events.

Unfortunately, the rtc-cmos driver does exactly the incorrect thing
by calling cmos_wake_setup(), which passes rtc_handler() to
acpi_install_fixed_event_handler(), before cmos_do_probe(), because
rtc_handler() uses dev_get_drvdata() to get to the cmos object
pointer and the driver data pointer is only populated in
cmos_do_probe().

This leads to a NULL pointer dereference in rtc_handler() on boot
if the RTC fixed event happens to be active at the init time.

To address this issue, change the initialization ordering of the
driver so that cmos_wake_setup() is always called after a successful
cmos_do_probe() call.

While at it, change cmos_pnp_probe() to call cmos_do_probe() after
the initial if () statement used for computing the IRQ argument to
be passed to cmos_do_probe() which is cleaner than calling it in
each branch of that if () (local variable "irq" can be of type int,
because it is passed to that function as an argument of type int).

Note that commit 6492fed7d8c9 ("rtc: rtc-cmos: Do not check
ACPI_FADT_LOW_POWER_S0") caused this issue to affect a larger number
of systems, because previously it only affected systems with
ACPI_FADT_LOW_POWER_S0 set, but it is present regardless of that
commit.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2022-48953?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-48953?

Apply the vendor's patch.

## Is CVE-2022-48953 being exploited?

There is no known exploitation of CVE-2022-48953 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-2022-48953 and fix it if it is affected.

What it is: CVE-2022-48953 is a medium-severity vulnerability in Linux kernel, published on 21 Oct 2024. 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-2022-48953 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-2022-48953/ (Markdown: https://insights.sbomify.com/CVE-2022-48953/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-48953
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-48953
- OSV: https://osv.dev/vulnerability/CVE-2022-48953

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-48953/
Summaries are generated and may contain mistakes; the official description above is the record.