# CVE-2026-31639: rxrpc: Fix key reference count leak from call->key

> A reference count leak in the Linux kernel's rxrpc module can lead to resource exhaustion and denial of service.

- **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:** 24 Apr 2026
- **Updated:** 11 May 2026
- **Also known as:** AZL-83816, BELL-CVE-2026-31639, DEBIAN-CVE-2026-31639, GHSA-4xm4-6p23-gp97, ROOT-OS-UBUNTU-2404-CVE-2026-31639, UBUNTU-CVE-2026-31639

## What is CVE-2026-31639?

CVE-2026-31639 is a medium-severity memory corruption vulnerability in Linux kernel, published on 24 Apr 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:

rxrpc: Fix key reference count leak from call->key

When creating a client call in rxrpc_alloc_client_call(), the code obtains
a reference to the key.  This is never cleaned up and gets leaked when the
call is destroyed.

Fix this by freeing call->key in rxrpc_destroy_call().

Before the patch, it shows the key reference counter elevated:

$ cat /proc/keys | grep afs@54321
1bffe9cd I--Q--i 8053480 4169w 3b010000  1000  1000 rxrpc     afs@54321: ka
$

After the patch, the invalidated key is removed when the code exits:

$ cat /proc/keys | grep afs@54321
$

## Which versions are affected by CVE-2026-31639?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31639?

Apply the vendor's patch.

## Is CVE-2026-31639 being exploited?

There is no known exploitation of CVE-2026-31639 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-2026-31639 and fix it if it is affected.

What it is: CVE-2026-31639 is a medium-severity memory corruption vulnerability in Linux kernel, published on 24 Apr 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-2026-31639 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-2026-31639/ (Markdown: https://insights.sbomify.com/CVE-2026-31639/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31639
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31639
- OSV: https://osv.dev/vulnerability/CVE-2026-31639

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31639/
Summaries are generated and may contain mistakes; the official description above is the record.