# CVE-2022-49390: macsec: fix UAF bug for real_dev

> A use-after-free vulnerability in the Linux kernel MACsec driver allows attackers to potentially execute code or escalate privileges.

- **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:** 26 Feb 2025
- **Updated:** 5 Aug 2026
- **Also known as:** DEBIAN-CVE-2022-49390, GHSA-w9jf-hmj5-fp54, ROOT-OS-DEBIAN-11-CVE-2022-49390, ROOT-OS-UBUNTU-2204-CVE-2022-49390, UBUNTU-CVE-2022-49390

## What is CVE-2022-49390?

CVE-2022-49390 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 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:

macsec: fix UAF bug for real_dev

Create a new macsec device but not get reference to real_dev. That can
not ensure that real_dev is freed after macsec. That will trigger the
UAF bug for real_dev as following:

==================================================================
BUG: KASAN: use-after-free in macsec_get_iflink+0x5f/0x70 drivers/net/macsec.c:3662
Call Trace:
 ...
 macsec_get_iflink+0x5f/0x70 drivers/net/macsec.c:3662
 dev_get_iflink+0x73/0xe0 net/core/dev.c:637
 default_operstate net/core/link_watch.c:42 [inline]
 rfc2863_policy+0x233/0x2d0 net/core/link_watch.c:54
 linkwatch_do_dev+0x2a/0x150 net/core/link_watch.c:161

Allocated by task 22209:
 ...
 alloc_netdev_mqs+0x98/0x1100 net/core/dev.c:10549
 rtnl_create_link+0x9d7/0xc00 net/core/rtnetlink.c:3235
 veth_newlink+0x20e/0xa90 drivers/net/veth.c:1748

Freed by task 8:
 ...
 kfree+0xd6/0x4d0 mm/slub.c:4552
 kvfree+0x42/0x50 mm/util.c:615
 device_release+0x9f/0x240 drivers/base/core.c:2229
 kobject_cleanup lib/kobject.c:673 [inline]
 kobject_release lib/kobject.c:704 [inline]
 kref_put include/linux/kref.h:65 [inline]
 kobject_put+0x1c8/0x540 lib/kobject.c:721
 netdev_run_todo+0x72e/0x10b0 net/core/dev.c:10327

After commit faab39f63c1f ("net: allow out-of-order netdev unregistration")
and commit e5f80fcf869a ("ipv6: give an IPv6 dev to blackhole_netdev"), we
can add dev_hold_track() in macsec_dev_init() and dev_put_track() in
macsec_free_netdev() to fix the problem.

Weakness: CWE-416 (Use After Free)

## Which versions are affected by CVE-2022-49390?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2022-49390?

Apply the vendor's patch.

## Is CVE-2022-49390 being exploited?

There is no known exploitation of CVE-2022-49390 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-2022-49390 and fix it if it is affected.

What it is: CVE-2022-49390 is a high-severity use after free vulnerability in Linux kernel, published on 26 Feb 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-2022-49390 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-2022-49390/ (Markdown: https://insights.sbomify.com/CVE-2022-49390/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2022-49390
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2022-49390
- OSV: https://osv.dev/vulnerability/CVE-2022-49390

---
From sbomify Insights: https://insights.sbomify.com/CVE-2022-49390/
Summaries are generated and may contain mistakes; the official description above is the record.