# CVE-2026-31660: nfc: pn533: allocate rx skb before consuming bytes

> A null pointer dereference in the Linux kernel NFC driver can cause a system crash when memory allocation fails during data reception.

- **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-83681, BELL-CVE-2026-31660, DEBIAN-CVE-2026-31660, GHSA-vh7f-9w49-q39v, ROOT-OS-DEBIAN-11-CVE-2026-31660, ROOT-OS-DEBIAN-12-CVE-2026-31660, ROOT-OS-UBUNTU-2204-CVE-2026-31660, ROOT-OS-UBUNTU-2404-CVE-2026-31660, UBUNTU-CVE-2026-31660

## What is CVE-2026-31660?

CVE-2026-31660 is a medium-severity 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:

nfc: pn533: allocate rx skb before consuming bytes

pn532_receive_buf() reports the number of accepted bytes to the serdev
core. The current code consumes bytes into recv_skb and may already hand
a complete frame to pn533_recv_frame() before allocating a fresh receive
buffer.

If that alloc_skb() fails, the callback returns 0 even though it has
already consumed bytes, and it leaves recv_skb as NULL for the next
receive callback. That breaks the receive_buf() accounting contract and
can also lead to a NULL dereference on the next skb_put_u8().

Allocate the receive skb lazily before consuming the next byte instead.
If allocation fails, return the number of bytes already accepted.

## Which versions are affected by CVE-2026-31660?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31660?

Apply the vendor's patch.

## Is CVE-2026-31660 being exploited?

There is no known exploitation of CVE-2026-31660 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-2026-31660 and fix it if it is affected.

What it is: CVE-2026-31660 is a medium-severity 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-2026-31660 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-2026-31660/ (Markdown: https://insights.sbomify.com/CVE-2026-31660/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31660
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31660
- OSV: https://osv.dev/vulnerability/CVE-2026-31660

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31660/
Summaries are generated and may contain mistakes; the official description above is the record.