# CVE-2025-38106: io_uring: fix use-after-free of sq->thread in __io_uring_show_fdinfo()

> A use-after-free vulnerability in the Linux kernel's io_uring subsystem allows local attackers to cause a system crash or potentially execute arbitrary code.

- **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:** 3 Jul 2025
- **Updated:** 5 Aug 2026
- **Also known as:** BELL-CVE-2025-38106, DEBIAN-CVE-2025-38106, GHSA-vh9v-7rrm-mm8x, UBUNTU-CVE-2025-38106

## What is CVE-2025-38106?

CVE-2025-38106 is a high-severity use after free vulnerability in Linux kernel, published on 3 Jul 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:

io_uring: fix use-after-free of sq->thread in __io_uring_show_fdinfo()

syzbot reports:

BUG: KASAN: slab-use-after-free in getrusage+0x1109/0x1a60
Read of size 8 at addr ffff88810de2d2c8 by task a.out/304

CPU: 0 UID: 0 PID: 304 Comm: a.out Not tainted 6.16.0-rc1 #1 PREEMPT(voluntary)
Hardware name: QEMU Ubuntu 24.04 PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0x53/0x70
 print_report+0xd0/0x670
 ? __pfx__raw_spin_lock_irqsave+0x10/0x10
 ? getrusage+0x1109/0x1a60
 kasan_report+0xce/0x100
 ? getrusage+0x1109/0x1a60
 getrusage+0x1109/0x1a60
 ? __pfx_getrusage+0x10/0x10
 __io_uring_show_fdinfo+0x9fe/0x1790
 ? ksys_read+0xf7/0x1c0
 ? do_syscall_64+0xa4/0x260
 ? vsnprintf+0x591/0x1100
 ? __pfx___io_uring_show_fdinfo+0x10/0x10
 ? __pfx_vsnprintf+0x10/0x10
 ? mutex_trylock+0xcf/0x130
 ? __pfx_mutex_trylock+0x10/0x10
 ? __pfx_show_fd_locks+0x10/0x10
 ? io_uring_show_fdinfo+0x57/0x80
 io_uring_show_fdinfo+0x57/0x80
 seq_show+0x38c/0x690
 seq_read_iter+0x3f7/0x1180
 ? inode_set_ctime_current+0x160/0x4b0
 seq_read+0x271/0x3e0
 ? __pfx_seq_read+0x10/0x10
 ? __pfx__raw_spin_lock+0x10/0x10
 ? __mark_inode_dirty+0x402/0x810
 ? selinux_file_permission+0x368/0x500
 ? file_update_time+0x10f/0x160
 vfs_read+0x177/0xa40
 ? __pfx___handle_mm_fault+0x10/0x10
 ? __pfx_vfs_read+0x10/0x10
 ? mutex_lock+0x81/0xe0
 ? __pfx_mutex_lock+0x10/0x10
 ? fdget_pos+0x24d/0x4b0
 ksys_read+0xf7/0x1c0
 ? __pfx_ksys_read+0x10/0x10
 ? do_user_addr_fault+0x43b/0x9c0
 do_syscall_64+0xa4/0x260
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f0f74170fc9
Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 8
RSP: 002b:00007fffece049e8 EFLAGS: 00000206 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f0f74170fc9
RDX: 0000000000001000 RSI: 00007fffece049f0 RDI: 0000000000000004
RBP: 00007fffece05ad0 R08: 0000000000000000 R09: 00007fffece04d90
R10: 0000000000000000 R11: 0000000000000206 R12: 00005651720a1100
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
 </TASK>

Allocated by task 298:
 kasan_save_stack+0x33/0x60
 kasan_save_track+0x14/0x30
 __kasan_slab_alloc+0x6e/0x70
 kmem_cache_alloc_node_noprof+0xe8/0x330
 copy_process+0x376/0x5e00
 create_io_thread+0xab/0xf0
 io_sq_offload_create+0x9ed/0xf20
 io_uring_setup+0x12b0/0x1cc0
 do_syscall_64+0xa4/0x260
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Freed by task 22:
 kasan_save_stack+0x33/0x60
 kasan_save_track+0x14/0x30
 kasan_save_free_info+0x3b/0x60
 __kasan_slab_free+0x37/0x50
 kmem_cache_free+0xc4/0x360
 rcu_core+0x5ff/0x19f0
 handle_softirqs+0x18c/0x530
 run_ksoftirqd+0x20/0x30
 smpboot_thread_fn+0x287/0x6c0
 kthread+0x30d/0x630
 ret_from_fork+0xef/0x1a0
 ret_from_fork_asm+0x1a/0x30

Last potentially related work creation:
 kasan_save_stack+0x33/0x60
 kasan_record_aux_stack+0x8c/0xa0
 __call_rcu_common.constprop.0+0x68/0x940
 __schedule+0xff2/0x2930
 __cond_resched+0x4c/0x80
 mutex_lock+0x5c/0xe0
 io_uring_del_tctx_node+0xe1/0x2b0
 io_uring_clean_tctx+0xb7/0x160
 io_uring_cancel_generic+0x34e/0x760
 do_exit+0x240/0x2350
 do_group_exit+0xab/0x220
 __x64_sys_exit_group+0x39/0x40
 x64_sys_call+0x1243/0x1840
 do_syscall_64+0xa4/0x260
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

The buggy address belongs to the object at ffff88810de2cb00
 which belongs to the cache task_struct of size 3712
The buggy address is located 1992 bytes inside of
 freed 3712-byte region [ffff88810de2cb00, ffff88810de2d980)

which is caused by the task_struct pointed to by sq->thread being
released while it is being used in the function
__io_uring_show_fdinfo(). Holding ctx->uring_lock does not prevent ehre
relase or exit of sq->thread.

Fix this by assigning and looking up ->thread under RCU, and grabbing a
reference to the task_struct. This e
---truncated---

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2025-38106?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2025-38106?

Apply the vendor's patch.

## Is CVE-2025-38106 being exploited?

There is no known exploitation of CVE-2025-38106 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-2025-38106 and fix it if it is affected.

What it is: CVE-2025-38106 is a high-severity use after free vulnerability in Linux kernel, published on 3 Jul 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-2025-38106 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-2025-38106/ (Markdown: https://insights.sbomify.com/CVE-2025-38106/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-38106
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-38106
- OSV: https://osv.dev/vulnerability/CVE-2025-38106

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-38106/
Summaries are generated and may contain mistakes; the official description above is the record.