---
title: "CVE-2026-89902: Linux Kernel - Privilege Escalation"
description: "Linux kernel contains a preempt count underflow vulnerability in LoongArch caused by improper handling of break 11 instruction in kprobe_singlestep_handler, letting attackers bypass socket cgroup policies, exploit requires triggering a userspace breakpoint."
url: https://panop.io/threat-heartbeat/CVE-2026-89902/
---

# CVE-2026-89902 Linux Kernel - Privilege Escalation

Linux kernel contains a preempt count underflow vulnerability in LoongArch caused by improper handling of break 11 instruction in kprobe\_singlestep\_handler, letting attackers bypass socket cgroup policies, exploit requires triggering a userspace breakpoint.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.18% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89902)

## Details

Type

Privilege Escalation

Impact

Privilege Escalation

CVSS vector

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

Published

16 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version containing the fix.

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-2026-89902](https://nvd.nist.gov/vuln/detail/CVE-2026-89902)
- [https://git.kernel.org/stable/c/72ce4b24676e8b3b75376c4c559dd81c1ac52d5a](https://git.kernel.org/stable/c/72ce4b24676e8b3b75376c4c559dd81c1ac52d5a)
- [https://git.kernel.org/stable/c/76395109a051b53860faaec96522ef08ae9e8e27](https://git.kernel.org/stable/c/76395109a051b53860faaec96522ef08ae9e8e27)
- [https://git.kernel.org/stable/c/a1cb727fa27c2d9c7859729cd90db7bc0f46957f](https://git.kernel.org/stable/c/a1cb727fa27c2d9c7859729cd90db7bc0f46957f)
- [https://git.kernel.org/stable/c/c4357ebeee63cb8da1446fc936573a34e68b0f71](https://git.kernel.org/stable/c/c4357ebeee63cb8da1446fc936573a34e68b0f71)
- [https://git.kernel.org/stable/c/ff40e597d5d98c0c45a4d09df8177202fac9520e](https://git.kernel.org/stable/c/ff40e597d5d98c0c45a4d09df8177202fac9520e)

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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

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