# CVE-2022-49892: ftrace: Fix use-after-free for dynamic ftrace_ops

> A use-after-free in the Linux kernel ftrace subsystem allows attackers to potentially execute code or escalate privileges via race conditions during ftrace operations.

- **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:** 1 May 2025
- **Updated:** 15 Oct 2026
- **Also known as:** DEBIAN-CVE-2022-49892, GHSA-w983-x7cf-qq48, UBUNTU-CVE-2022-49892

## What is CVE-2022-49892?

CVE-2022-49892 is a high-severity use after free vulnerability in Linux kernel, published on 1 May 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:

ftrace: Fix use-after-free for dynamic ftrace_ops

KASAN reported a use-after-free with ftrace ops [1]. It was found from
vmcore that perf had registered two ops with the same content
successively, both dynamic. After unregistering the second ops, a
use-after-free occurred.

In ftrace_shutdown(), when the second ops is unregistered, the
FTRACE_UPDATE_CALLS command is not set because there is another enabled
ops with the same content.  Also, both ops are dynamic and the ftrace
callback function is ftrace_ops_list_func, so the
FTRACE_UPDATE_TRACE_FUNC command will not be set. Eventually the value
of 'command' will be 0 and ftrace_shutdown() will skip the rcu
synchronization.

However, ftrace may be activated. When the ops is released, another CPU
may be accessing the ops.  Add the missing synchronization to fix this
problem.

[1]
BUG: KASAN: use-after-free in __ftrace_ops_list_func kernel/trace/ftrace.c:7020 [inline]
BUG: KASAN: use-after-free in ftrace_ops_list_func+0x2b0/0x31c kernel/trace/ftrace.c:7049
Read of size 8 at addr ffff56551965bbc8 by task syz-executor.2/14468

CPU: 1 PID: 14468 Comm: syz-executor.2 Not tainted 5.10.0 #7
Hardware name: linux,dummy-virt (DT)
Call trace:
 dump_backtrace+0x0/0x40c arch/arm64/kernel/stacktrace.c:132
 show_stack+0x30/0x40 arch/arm64/kernel/stacktrace.c:196
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b4/0x248 lib/dump_stack.c:118
 print_address_description.constprop.0+0x28/0x48c mm/kasan/report.c:387
 __kasan_report mm/kasan/report.c:547 [inline]
 kasan_report+0x118/0x210 mm/kasan/report.c:564
 check_memory_region_inline mm/kasan/generic.c:187 [inline]
 __asan_load8+0x98/0xc0 mm/kasan/generic.c:253
 __ftrace_ops_list_func kernel/trace/ftrace.c:7020 [inline]
 ftrace_ops_list_func+0x2b0/0x31c kernel/trace/ftrace.c:7049
 ftrace_graph_call+0x0/0x4
 __might_sleep+0x8/0x100 include/linux/perf_event.h:1170
 __might_fault mm/memory.c:5183 [inline]
 __might_fault+0x58/0x70 mm/memory.c:5171
 do_strncpy_from_user lib/strncpy_from_user.c:41 [inline]
 strncpy_from_user+0x1f4/0x4b0 lib/strncpy_from_user.c:139
 getname_flags+0xb0/0x31c fs/namei.c:149
 getname+0x2c/0x40 fs/namei.c:209
 [...]

Allocated by task 14445:
 kasan_save_stack+0x24/0x50 mm/kasan/common.c:48
 kasan_set_track mm/kasan/common.c:56 [inline]
 __kasan_kmalloc mm/kasan/common.c:479 [inline]
 __kasan_kmalloc.constprop.0+0x110/0x13c mm/kasan/common.c:449
 kasan_kmalloc+0xc/0x14 mm/kasan/common.c:493
 kmem_cache_alloc_trace+0x440/0x924 mm/slub.c:2950
 kmalloc include/linux/slab.h:563 [inline]
 kzalloc include/linux/slab.h:675 [inline]
 perf_event_alloc.part.0+0xb4/0x1350 kernel/events/core.c:11230
 perf_event_alloc kernel/events/core.c:11733 [inline]
 __do_sys_perf_event_open kernel/events/core.c:11831 [inline]
 __se_sys_perf_event_open+0x550/0x15f4 kernel/events/core.c:11723
 __arm64_sys_perf_event_open+0x6c/0x80 kernel/events/core.c:11723
 [...]

Freed by task 14445:
 kasan_save_stack+0x24/0x50 mm/kasan/common.c:48
 kasan_set_track+0x24/0x34 mm/kasan/common.c:56
 kasan_set_free_info+0x20/0x40 mm/kasan/generic.c:358
 __kasan_slab_free.part.0+0x11c/0x1b0 mm/kasan/common.c:437
 __kasan_slab_free mm/kasan/common.c:445 [inline]
 kasan_slab_free+0x2c/0x40 mm/kasan/common.c:446
 slab_free_hook mm/slub.c:1569 [inline]
 slab_free_freelist_hook mm/slub.c:1608 [inline]
 slab_free mm/slub.c:3179 [inline]
 kfree+0x12c/0xc10 mm/slub.c:4176
 perf_event_alloc.part.0+0xa0c/0x1350 kernel/events/core.c:11434
 perf_event_alloc kernel/events/core.c:11733 [inline]
 __do_sys_perf_event_open kernel/events/core.c:11831 [inline]
 __se_sys_perf_event_open+0x550/0x15f4 kernel/events/core.c:11723
 [...]

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2022-49892?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-49892?

Apply the vendor's patch.

## Is CVE-2022-49892 being exploited?

There is no known exploitation of CVE-2022-49892 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-2022-49892 and fix it if it is affected.

What it is: CVE-2022-49892 is a high-severity use after free vulnerability in Linux kernel, published on 1 May 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-2022-49892 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-2022-49892/ (Markdown: https://insights.sbomify.com/CVE-2022-49892/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-49892
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-49892
- OSV: https://osv.dev/vulnerability/CVE-2022-49892

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-49892/
Summaries are generated and may contain mistakes; the official description above is the record.