# CVE-2022-48983: io_uring: Fix a null-ptr-deref in io_tctx_exit_cb()

> A null pointer dereference in the Linux kernel's io_uring subsystem allows local attackers to cause a system crash via a race condition.

- **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:** 21 Oct 2024
- **Updated:** 11 May 2026
- **Also known as:** DEBIAN-CVE-2022-48983, GHSA-2482-hx3h-75g4, UBUNTU-CVE-2022-48983

## What is CVE-2022-48983?

CVE-2022-48983 is a medium-severity vulnerability in Linux kernel, published on 21 Oct 2024. 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:

io_uring: Fix a null-ptr-deref in io_tctx_exit_cb()

Syzkaller reports a NULL deref bug as follows:

 BUG: KASAN: null-ptr-deref in io_tctx_exit_cb+0x53/0xd3
 Read of size 4 at addr 0000000000000138 by task file1/1955

 CPU: 1 PID: 1955 Comm: file1 Not tainted 6.1.0-rc7-00103-gef4d3ea40565 #75
 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
 Call Trace:
  <TASK>
  dump_stack_lvl+0xcd/0x134
  ? io_tctx_exit_cb+0x53/0xd3
  kasan_report+0xbb/0x1f0
  ? io_tctx_exit_cb+0x53/0xd3
  kasan_check_range+0x140/0x190
  io_tctx_exit_cb+0x53/0xd3
  task_work_run+0x164/0x250
  ? task_work_cancel+0x30/0x30
  get_signal+0x1c3/0x2440
  ? lock_downgrade+0x6e0/0x6e0
  ? lock_downgrade+0x6e0/0x6e0
  ? exit_signals+0x8b0/0x8b0
  ? do_raw_read_unlock+0x3b/0x70
  ? do_raw_spin_unlock+0x50/0x230
  arch_do_signal_or_restart+0x82/0x2470
  ? kmem_cache_free+0x260/0x4b0
  ? putname+0xfe/0x140
  ? get_sigframe_size+0x10/0x10
  ? do_execveat_common.isra.0+0x226/0x710
  ? lockdep_hardirqs_on+0x79/0x100
  ? putname+0xfe/0x140
  ? do_execveat_common.isra.0+0x238/0x710
  exit_to_user_mode_prepare+0x15f/0x250
  syscall_exit_to_user_mode+0x19/0x50
  do_syscall_64+0x42/0xb0
  entry_SYSCALL_64_after_hwframe+0x63/0xcd
 RIP: 0023:0x0
 Code: Unable to access opcode bytes at 0xffffffffffffffd6.
 RSP: 002b:00000000fffb7790 EFLAGS: 00000200 ORIG_RAX: 000000000000000b
 RAX: 0000000000000000 RBX: 0000000000000000 RCX: 0000000000000000
 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
  </TASK>
 Kernel panic - not syncing: panic_on_warn set ...

This happens because the adding of task_work from io_ring_exit_work()
isn't synchronized with canceling all work items from eg exec. The
execution of the two are ordered in that they are both run by the task
itself, but if io_tctx_exit_cb() is queued while we're canceling all
work items off exec AND gets executed when the task exits to userspace
rather than in the main loop in io_uring_cancel_generic(), then we can
find current->io_uring == NULL and hit the above crash.

It's safe to add this NULL check here, because the execution of the two
paths are done by the task itself.

[axboe: add code comment and also put an explanation in the commit msg]

Weakness: CWE-476 (NULL Pointer Dereference)

## Which versions are affected by CVE-2022-48983?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-48983?

Apply the vendor's patch.

## Is CVE-2022-48983 being exploited?

There is no known exploitation of CVE-2022-48983 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-2022-48983 and fix it if it is affected.

What it is: CVE-2022-48983 is a medium-severity vulnerability in Linux kernel, published on 21 Oct 2024. 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-2022-48983 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-2022-48983/ (Markdown: https://insights.sbomify.com/CVE-2022-48983/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-48983
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-48983
- OSV: https://osv.dev/vulnerability/CVE-2022-48983

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-48983/
Summaries are generated and may contain mistakes; the official description above is the record.