# CVE-2026-31629: nfc: llcp: add missing return after LLCP_CLOSED checks

> A missing return statement in the Linux kernel NFC LLCP handler causes a use-after-free, potentially allowing local attackers to execute code or escalate privileges.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/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:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Apr 2026
- **Updated:** 15 Oct 2026
- **Also known as:** A-499350302, ASB-A-499350302, AZL-83822, BELL-CVE-2026-31629, DEBIAN-CVE-2026-31629, GHSA-cfpg-q83x-6923, ROOT-OS-DEBIAN-11-CVE-2026-31629, ROOT-OS-DEBIAN-12-CVE-2026-31629, ROOT-OS-UBUNTU-2204-CVE-2026-31629, ROOT-OS-UBUNTU-2404-CVE-2026-31629, UBUNTU-CVE-2026-31629

## What is CVE-2026-31629?

CVE-2026-31629 is a high-severity use after free 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: llcp: add missing return after LLCP_CLOSED checks

In nfc_llcp_recv_hdlc() and nfc_llcp_recv_disc(), when the socket
state is LLCP_CLOSED, the code correctly calls release_sock() and
nfc_llcp_sock_put() but fails to return. Execution falls through to
the remainder of the function, which calls release_sock() and
nfc_llcp_sock_put() again. This results in a double release_sock()
and a refcount underflow via double nfc_llcp_sock_put(), leading to
a use-after-free.

Add the missing return statements after the LLCP_CLOSED branches
in both functions to prevent the fall-through.

Weakness: CWE-667 (Improper Locking)

## Which versions are affected by CVE-2026-31629?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31629?

Apply the vendor's patch.

## Is CVE-2026-31629 being exploited?

There is no known exploitation of CVE-2026-31629 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-2026-31629 and fix it if it is affected.

What it is: CVE-2026-31629 is a high-severity use after free 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-2026-31629 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-2026-31629/ (Markdown: https://insights.sbomify.com/CVE-2026-31629/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31629
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31629
- OSV: https://osv.dev/vulnerability/CVE-2026-31629

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31629/
Summaries are generated and may contain mistakes; the official description above is the record.