# CVE-2021-47453: ice: Avoid crash from unnecessary IDA free

> A null pointer dereference in the Intel ice driver can cause a kernel crash when unloading the driver on systems without RDMA support.

- **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:** 22 May 2024
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2021-47453, GHSA-hpj2-q4fg-98gf, UBUNTU-CVE-2021-47453

## What is CVE-2021-47453?

CVE-2021-47453 is a medium-severity vulnerability in Linux kernel, published on 22 May 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:

ice: Avoid crash from unnecessary IDA free

In the remove path, there is an attempt to free the aux_idx IDA whether
it was allocated or not.  This can potentially cause a crash when
unloading the driver on systems that do not initialize support for RDMA.
But, this free cannot be gated by the status bit for RDMA, since it is
allocated if the driver detects support for RDMA at probe time, but the
driver can enter into a state where RDMA is not supported after the IDA
has been allocated at probe time and this would lead to a memory leak.

Initialize aux_idx to an invalid value and check for a valid value when
unloading to determine if an IDA free is necessary.

Weakness: CWE-401 (Missing Release of Memory after Effective Lifetime)

## Which versions are affected by CVE-2021-47453?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47453?

Apply the vendor's patch.

## Is CVE-2021-47453 being exploited?

There is no known exploitation of CVE-2021-47453 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-2021-47453 and fix it if it is affected.

What it is: CVE-2021-47453 is a medium-severity vulnerability in Linux kernel, published on 22 May 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-2021-47453 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-2021-47453/ (Markdown: https://insights.sbomify.com/CVE-2021-47453/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47453
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47453
- OSV: https://osv.dev/vulnerability/CVE-2021-47453

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47453/
Summaries are generated and may contain mistakes; the official description above is the record.