# CVE-2026-23239: espintcp: Fix race condition in espintcp_close()

> A race condition in the Linux kernel's espintcp module allows a use-after-free, potentially causing a system crash or denial of service.

- **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:** 10 Mar 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-23239, DEBIAN-CVE-2026-23239, GHSA-246x-p35q-qhcq, ROOT-OS-DEBIAN-11-CVE-2026-23239, ROOT-OS-DEBIAN-12-CVE-2026-23239, ROOT-OS-DEBIAN-13-CVE-2026-23239, ROOT-OS-UBUNTU-2204-CVE-2026-23239, ROOT-OS-UBUNTU-2404-CVE-2026-23239, UBUNTU-CVE-2026-23239

## What is CVE-2026-23239?

CVE-2026-23239 is a high-severity vulnerability in Linux kernel, published on 10 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:

espintcp: Fix race condition in espintcp_close()

This issue was discovered during a code audit.

After cancel_work_sync() is called from espintcp_close(),
espintcp_tx_work() can still be scheduled from paths such as
the Delayed ACK handler or ksoftirqd.
As a result, the espintcp_tx_work() worker may dereference a
freed espintcp ctx or sk.

The following is a simple race scenario:

           cpu0                             cpu1

  espintcp_close()
    cancel_work_sync(&ctx->work);
                                     espintcp_write_space()
                                       schedule_work(&ctx->work);

To prevent this race condition, cancel_work_sync() is
replaced with disable_work_sync().

Weakness: CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization)

## Which versions are affected by CVE-2026-23239?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-23239?

Apply the vendor's patch.

## Is CVE-2026-23239 being exploited?

There is no known exploitation of CVE-2026-23239 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-2026-23239 and fix it if it is affected.

What it is: CVE-2026-23239 is a high-severity vulnerability in Linux kernel, published on 10 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-2026-23239 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-2026-23239/ (Markdown: https://insights.sbomify.com/CVE-2026-23239/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-23239
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-23239
- OSV: https://osv.dev/vulnerability/CVE-2026-23239

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-23239/
Summaries are generated and may contain mistakes; the official description above is the record.