# CVE-2026-43197: netconsole: avoid OOB reads, msg is not nul-terminated

> Out-of-bounds read in Linux kernel netconsole due to missing null termination, potentially causing crashes or information leaks.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 May 2026
- **Updated:** 21 Oct 2026
- **Also known as:** AZL-85830, BELL-CVE-2026-43197, DEBIAN-CVE-2026-43197, GHSA-25mj-mfqw-xqm2, ROOT-OS-DEBIAN-13-CVE-2026-43197, ROOT-OS-UBUNTU-2404-CVE-2026-43197, UBUNTU-CVE-2026-43197

## What is CVE-2026-43197?

CVE-2026-43197 is a critical memory corruption vulnerability in Linux kernel, published on 6 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

netconsole: avoid OOB reads, msg is not nul-terminated

msg passed to netconsole from the console subsystem is not guaranteed
to be nul-terminated. Before recent
commit 7eab73b18630 ("netconsole: convert to NBCON console infrastructure")
the message would be placed in printk_shared_pbufs, a static global
buffer, so KASAN had harder time catching OOB accesses. Now we see:

    printk: console [netcon_ext0] enabled
    BUG: KASAN: slab-out-of-bounds in string+0x1f7/0x240
    Read of size 1 at addr ffff88813b6d4c00 by task pr/netcon_ext0/594

    CPU: 65 UID: 0 PID: 594 Comm: pr/netcon_ext0 Not tainted 6.19.0-11754-g4246fd6547c9
    Call Trace:
     kasan_report+0xe4/0x120
     string+0x1f7/0x240
     vsnprintf+0x655/0xba0
     scnprintf+0xba/0x120
     netconsole_write+0x3fe/0xa10
     nbcon_emit_next_record+0x46e/0x860
     nbcon_kthread_func+0x623/0x750

    Allocated by task 1:
     nbcon_alloc+0x1ea/0x450
     register_console+0x26b/0xe10
     init_netconsole+0xbb0/0xda0

    The buggy address belongs to the object at ffff88813b6d4000
                which belongs to the cache kmalloc-4k of size 4096
    The buggy address is located 0 bytes to the right of
                allocated 3072-byte region [ffff88813b6d4000, ffff88813b6d4c00)

Weakness: CWE-125 (Out-of-bounds Read)

## Which versions are affected by CVE-2026-43197?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-43197?

Apply the vendor's patch.

## Is CVE-2026-43197 being exploited?

There is no known exploitation of CVE-2026-43197 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-2026-43197 and fix it if it is affected.

What it is: CVE-2026-43197 is a critical memory corruption vulnerability in Linux kernel, published on 6 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-43197 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-2026-43197/ (Markdown: https://insights.sbomify.com/CVE-2026-43197/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43197
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43197
- OSV: https://osv.dev/vulnerability/CVE-2026-43197

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-43197/
Summaries are generated and may contain mistakes; the official description above is the record.