# CVE-2022-50555: tipc: fix a null-ptr-deref in tipc_topsrv_accept

> A null pointer dereference in the Linux kernel's TIPC module allows local attackers to cause a system crash via a race condition during service shutdown.

- **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:** 7 Oct 2025
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-50555, GHSA-6jh6-f787-4g5p, UBUNTU-CVE-2022-50555

## What is CVE-2022-50555?

CVE-2022-50555 is a high-severity vulnerability in Linux kernel, published on 7 Oct 2025. 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:

tipc: fix a null-ptr-deref in tipc_topsrv_accept

syzbot found a crash in tipc_topsrv_accept:

  KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f]
  Workqueue: tipc_rcv tipc_topsrv_accept
  RIP: 0010:kernel_accept+0x22d/0x350 net/socket.c:3487
  Call Trace:
   <TASK>
   tipc_topsrv_accept+0x197/0x280 net/tipc/topsrv.c:460
   process_one_work+0x991/0x1610 kernel/workqueue.c:2289
   worker_thread+0x665/0x1080 kernel/workqueue.c:2436
   kthread+0x2e4/0x3a0 kernel/kthread.c:376
   ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306

It was caused by srv->listener that might be set to null by
tipc_topsrv_stop() in net .exit whereas it's still used in
tipc_topsrv_accept() worker.

srv->listener is protected by srv->idr_lock in tipc_topsrv_stop(), so add
a check for srv->listener under srv->idr_lock in tipc_topsrv_accept() to
avoid the null-ptr-deref. To ensure the lsock is not released during the
tipc_topsrv_accept(), move sock_release() after tipc_topsrv_work_stop()
where it's waiting until the tipc_topsrv_accept worker to be done.

Note that sk_callback_lock is used to protect sk->sk_user_data instead of
srv->listener, and it should check srv in tipc_topsrv_listener_data_ready()
instead. This also ensures that no more tipc_topsrv_accept worker will be
started after tipc_conn_close() is called in tipc_topsrv_stop() where it
sets sk->sk_user_data to null.

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2022-50555?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-50555?

Apply the vendor's patch.

## Is CVE-2022-50555 being exploited?

There is no known exploitation of CVE-2022-50555 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-2022-50555 and fix it if it is affected.

What it is: CVE-2022-50555 is a high-severity vulnerability in Linux kernel, published on 7 Oct 2025. 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-2022-50555 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-2022-50555/ (Markdown: https://insights.sbomify.com/CVE-2022-50555/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-50555
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-50555
- OSV: https://osv.dev/vulnerability/CVE-2022-50555

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-50555/
Summaries are generated and may contain mistakes; the official description above is the record.