---
title: "CVE-2026-98976: Linux Kernel - Broken Access Control"
description: "Linux kernel contains a privilege escalation vulnerability caused by improper lock transfer on propagated mounts in user namespaces, letting user namespace owners unmount locked covers and access restricted files, exploit requires user namespace ownership."
url: https://panop.io/threat-heartbeat/CVE-2026-98976/
---

# CVE-2026-98976 Linux Kernel - Broken Access Control

Linux kernel contains a privilege escalation vulnerability caused by improper lock transfer on propagated mounts in user namespaces, letting user namespace owners unmount locked covers and access restricted files, exploit requires user namespace ownership.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.20% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-98976)

## Details

Type

Broken Access Control

Impact

Privilege Escalation, Information Disclosure

CVSS vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Published

23 October 2026

Updated

25 October 2026

## Vendor fix

Update to the latest Linux kernel version with the fix for mount lock transfer.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-98976](https://nvd.nist.gov/vuln/detail/CVE-2026-98976)
- [https://git.kernel.org/stable/c/d74d66aa708ccf2bc0b1e265a83fed0f2308d5c4](https://git.kernel.org/stable/c/d74d66aa708ccf2bc0b1e265a83fed0f2308d5c4)
- [https://git.kernel.org/stable/c/f1f0c24ca701d7d3061c7f69f7450f1734c11745](https://git.kernel.org/stable/c/f1f0c24ca701d7d3061c7f69f7450f1734c11745)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

Panop answers these inside your environment, for this CVE and every other finding.

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