---
title: "CVE-2026-79979: Linux Kernel - Broken Access Control"
description: "The arm64 MMU backend in Linux kernel with CONFIG_USERSPACE and CONFIG_DEMAND_PAGING enabled contains a memory isolation bypass caused by improper TLB invalidation that only targets ASID 0, letting unprivileged user threads access stale mappings of kernel or other domain memory, exploit requires demand-paged pages privately mapped into a user memory domain."
url: https://panop.io/threat-heartbeat/CVE-2026-79979/
---

# CVE-2026-79979 Linux Kernel - Broken Access Control

The arm64 MMU backend in Linux kernel with CONFIG\_USERSPACE and CONFIG\_DEMAND\_PAGING enabled contains a memory isolation bypass caused by improper TLB invalidation that only targets ASID 0, letting unprivileged user threads access stale mappings of kernel or other domain memory, exploit requires demand-paged pages privately mapped into a user memory domain.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

EPSS

0.14% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-79979)

## Details

Type

Broken Access Control

Impact

Information Disclosure, Data Tampering, Privilege Escalation

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

Weakness

[CWE-416](https://cwe.mitre.org/data/definitions/416.html)

## Vendor fix

Update to a kernel version that includes the fix switching to TLBI VAAE1{IS} for proper TLB invalidation.

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-2026-79979](https://nvd.nist.gov/vuln/detail/CVE-2026-79979)
- [https://github.com/zephyrproject-rtos/zephyr/commit/d732e9f808f16911d06769b3f756246f3528669f](https://github.com/zephyrproject-rtos/zephyr/commit/d732e9f808f16911d06769b3f756246f3528669f)
- [https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-6pqm-hfxf-48qv](https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-6pqm-hfxf-48qv)

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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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