# CVE-2026-80929: sysctl: move the "cad_pid" entry from pid_table[] to kern_reboot_table[]

> A non-root user can modify the global cad_pid sysctl via namespace unsharing, potentially leading to privilege escalation or system instability.

- **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:** 11 Sep 2026
- **Updated:** 19 Oct 2026
- **Also known as:** BELL-CVE-2026-80929, DEBIAN-CVE-2026-80929, GHSA-5367-6mxw-83v4, UBUNTU-CVE-2026-80929

## What is CVE-2026-80929?

CVE-2026-80929 is a high-severity vulnerability in Linux, published on 11 Sep 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:

sysctl: move the "cad_pid" entry from pid_table[] to kern_reboot_table[]

cad_pid is global, and kill_cad_pid() is only used in the root namespace.

However, due to pid_table_root_permissions(), a non-root user can unshare
pid/user namespaces and modify it from the child namespace. This makes no
sense and is simply wrong.

Move it to kern_reboot_table[] where it logically belongs; this ensures
that only GLOBAL_ROOT_UID can read/modify this sysctl.

Note that this patch doesn't preserve "#ifdef CONFIG_PROC_SYSCTL" around
the "cad_pid"; CONFIG_PROC_SYSCTL selects CONFIG_SYSCTL, so it is always
set when kern_reboot_table[] is compiled.

## Which versions are affected by CVE-2026-80929?


## How do I fix CVE-2026-80929?

Apply the vendor's patch.

## Is CVE-2026-80929 being exploited?

There is no known exploitation of CVE-2026-80929 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80929 and fix it if it is affected.

What it is: CVE-2026-80929 is a high-severity vulnerability in Linux, published on 11 Sep 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-2026-80929 in the wild and no public exploit code.

Affected product: Linux. 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-2026-80929/ (Markdown: https://insights.sbomify.com/CVE-2026-80929/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80929
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80929
- OSV: https://osv.dev/vulnerability/CVE-2026-80929

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80929/
Summaries are generated and may contain mistakes; the official description above is the record.