# CVE-2026-23323: hwmon: (macsmc) Fix regressions in Apple Silicon SMC hwmon driver

> Out-of-bounds memory access in the Apple Silicon SMC hwmon driver allows potential code execution or system crash due to incorrect sensor array assignment.

- **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:** 25 Mar 2026
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2026-23323, GHSA-xf4v-3mcr-w96x, UBUNTU-CVE-2026-23323

## What is CVE-2026-23323?

CVE-2026-23323 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Mar 2026. 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:

hwmon: (macsmc) Fix regressions in Apple Silicon SMC hwmon driver

The recently added macsmc-hwmon driver contained several critical
bugs in its sensor population logic and float conversion routines.

Specifically:
- The voltage sensor population loop used the wrong prefix ("volt-"
  instead of "voltage-") and incorrectly assigned sensors to the
  temperature sensor array (hwmon->temp.sensors) instead of the
  voltage sensor array (hwmon->volt.sensors). This would lead to
  out-of-bounds memory access or data corruption when both temperature
  and voltage sensors were present.
- The float conversion in macsmc_hwmon_write_f32() had flawed exponent
  logic for values >= 2^24 and lacked masking for the mantissa, which
  could lead to incorrect values being written to the SMC.

Fix these issues to ensure correct sensor registration and reliable
manual fan control.

Confirm that the reported overflow in FIELD_PREP is fixed by declaring
macsmc_hwmon_write_f32() as __always_inline for a compile test.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-23323?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23323?

Apply the vendor's patch.

## Is CVE-2026-23323 being exploited?

There is no known exploitation of CVE-2026-23323 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-2026-23323 and fix it if it is affected.

What it is: CVE-2026-23323 is a high-severity memory corruption vulnerability in Linux kernel, published on 25 Mar 2026. 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-2026-23323 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-2026-23323/ (Markdown: https://insights.sbomify.com/CVE-2026-23323/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23323
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23323
- OSV: https://osv.dev/vulnerability/CVE-2026-23323

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23323/
Summaries are generated and may contain mistakes; the official description above is the record.