# CVE-2026-31494: net: macb: use the current queue number for stats

> A local attacker can trigger an out-of-bounds write in the macb network driver via ethtool, potentially leading to code execution or system crash.

- **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:** 22 Apr 2026
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-83372, BELL-CVE-2026-31494, DEBIAN-CVE-2026-31494, GHSA-ww72-rr4h-c932, ROOT-OS-DEBIAN-11-CVE-2026-31494, ROOT-OS-DEBIAN-12-CVE-2026-31494, ROOT-OS-UBUNTU-2204-CVE-2026-31494, ROOT-OS-UBUNTU-2404-CVE-2026-31494, UBUNTU-CVE-2026-31494

## What is CVE-2026-31494?

CVE-2026-31494 is a high-severity memory corruption vulnerability in Linux kernel, published on 22 Apr 2026. 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:

net: macb: use the current queue number for stats

There's a potential mismatch between the memory reserved for statistics
and the amount of memory written.

gem_get_sset_count() correctly computes the number of stats based on the
active queues, whereas gem_get_ethtool_stats() indiscriminately copies
data using the maximum number of queues, and in the case the number of
active queues is less than MACB_MAX_QUEUES, this results in a OOB write
as observed in the KASAN splat.

==================================================================
BUG: KASAN: vmalloc-out-of-bounds in gem_get_ethtool_stats+0x54/0x78
  [macb]
Write of size 760 at addr ffff80008080b000 by task ethtool/1027

CPU: [...]
Tainted: [E]=UNSIGNED_MODULE
Hardware name: raspberrypi rpi/rpi, BIOS 2025.10 10/01/2025
Call trace:
 show_stack+0x20/0x38 (C)
 dump_stack_lvl+0x80/0xf8
 print_report+0x384/0x5e0
 kasan_report+0xa0/0xf0
 kasan_check_range+0xe8/0x190
 __asan_memcpy+0x54/0x98
 gem_get_ethtool_stats+0x54/0x78 [macb
   926c13f3af83b0c6fe64badb21ec87d5e93fcf65]
 dev_ethtool+0x1220/0x38c0
 dev_ioctl+0x4ac/0xca8
 sock_do_ioctl+0x170/0x1d8
 sock_ioctl+0x484/0x5d8
 __arm64_sys_ioctl+0x12c/0x1b8
 invoke_syscall+0xd4/0x258
 el0_svc_common.constprop.0+0xb4/0x240
 do_el0_svc+0x48/0x68
 el0_svc+0x40/0xf8
 el0t_64_sync_handler+0xa0/0xe8
 el0t_64_sync+0x1b0/0x1b8

The buggy address belongs to a 1-page vmalloc region starting at
  0xffff80008080b000 allocated at dev_ethtool+0x11f0/0x38c0
The buggy address belongs to the physical page:
page: refcount:1 mapcount:0 mapping:0000000000000000
  index:0xffff00000a333000 pfn:0xa333
flags: 0x7fffc000000000(node=0|zone=0|lastcpupid=0x1ffff)
raw: 007fffc000000000 0000000000000000 dead000000000122 0000000000000000
raw: ffff00000a333000 0000000000000000 00000001ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff80008080b080: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff80008080b100: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
>ffff80008080b180: 00 00 00 00 00 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
                                  ^
 ffff80008080b200: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
 ffff80008080b280: f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8 f8
==================================================================

Fix it by making sure the copied size only considers the active number of
queues.

Weakness: CWE-787 (Out-of-bounds Write)

## Which versions are affected by CVE-2026-31494?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-31494?

Apply the vendor's patch.

## Is CVE-2026-31494 being exploited?

There is no known exploitation of CVE-2026-31494 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-2026-31494 and fix it if it is affected.

What it is: CVE-2026-31494 is a high-severity memory corruption vulnerability in Linux kernel, published on 22 Apr 2026. 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-2026-31494 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-2026-31494/ (Markdown: https://insights.sbomify.com/CVE-2026-31494/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-31494
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-31494
- OSV: https://osv.dev/vulnerability/CVE-2026-31494

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-31494/
Summaries are generated and may contain mistakes; the official description above is the record.