# CVE-2021-46953: ACPI: GTDT: Don't corrupt interrupt mappings on watchdow probe failure

> A flaw in the Linux kernel ACPI GTDT driver allows unmapping valid interrupts on probe failure, potentially causing system instability or denial of service.

- **Severity:** Medium 6.7 (`CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** An administrator
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 27 Feb 2024
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2021-46953, GHSA-2wwc-57w4-gp7m, UBUNTU-CVE-2021-46953

## What is CVE-2021-46953?

CVE-2021-46953 is a medium-severity vulnerability in Linux kernel, published on 27 Feb 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:

ACPI: GTDT: Don't corrupt interrupt mappings on watchdow probe failure

When failing the driver probe because of invalid firmware properties,
the GTDT driver unmaps the interrupt that it mapped earlier.

However, it never checks whether the mapping of the interrupt actially
succeeded. Even more, should the firmware report an illegal interrupt
number that overlaps with the GIC SGI range, this can result in an
IPI being unmapped, and subsequent fireworks (as reported by Dann
Frazier).

Rework the driver to have a slightly saner behaviour and actually
check whether the interrupt has been mapped before unmapping things.

## Which versions are affected by CVE-2021-46953?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-46953?

Apply the vendor's patch.

## Is CVE-2021-46953 being exploited?

There is no known exploitation of CVE-2021-46953 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-2021-46953 and fix it if it is affected.

What it is: CVE-2021-46953 is a medium-severity vulnerability in Linux kernel, published on 27 Feb 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-2021-46953 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-2021-46953/ (Markdown: https://insights.sbomify.com/CVE-2021-46953/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-46953
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-46953
- OSV: https://osv.dev/vulnerability/CVE-2021-46953

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-46953/
Summaries are generated and may contain mistakes; the official description above is the record.