# CVE-2021-47427: scsi: iscsi: Fix iscsi_task use after free

> A use-after-free vulnerability in the Linux kernel's iSCSI subsystem allows attackers to potentially execute arbitrary code or escalate privileges.

- **Severity:** Critical 9.8 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 21 May 2024
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2021-47427, GHSA-rxcf-2w24-j9pq, UBUNTU-CVE-2021-47427

## What is CVE-2021-47427?

CVE-2021-47427 is a critical use after free vulnerability in Linux kernel, published on 21 May 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

scsi: iscsi: Fix iscsi_task use after free

Commit d39df158518c ("scsi: iscsi: Have abort handler get ref to conn")
added iscsi_get_conn()/iscsi_put_conn() calls during abort handling but
then also changed the handling of the case where we detect an already
completed task where we now end up doing a goto to the common put/cleanup
code. This results in a iscsi_task use after free, because the common
cleanup code will do a put on the iscsi_task.

This reverts the goto and moves the iscsi_get_conn() to after we've checked
if the iscsi_task is valid.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2021-47427?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2021-47427?

Apply the vendor's patch.

## Is CVE-2021-47427 being exploited?

There is no known exploitation of CVE-2021-47427 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-2021-47427 and fix it if it is affected.

What it is: CVE-2021-47427 is a critical use after free vulnerability in Linux kernel, published on 21 May 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2021-47427 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-2021-47427/ (Markdown: https://insights.sbomify.com/CVE-2021-47427/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47427
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47427
- OSV: https://osv.dev/vulnerability/CVE-2021-47427

---
From sbomify Insights: https://insights.sbomify.com/CVE-2021-47427/
Summaries are generated and may contain mistakes; the official description above is the record.