---
title: "CVE-2026-89646: Linux Kernel Ceph - Broken Access Control"
description: "Linux kernel contains a broken access control vulnerability in Ceph where leaked inode references occur on writeback abort during umount, caused by failure to release wrbuffer claims, letting attackers cause inode eviction failure, exploit requires umount operation."
url: https://panop.io/threat-heartbeat/CVE-2026-89646/
---

# CVE-2026-89646 Linux Kernel Ceph - Broken Access Control

Linux kernel contains a broken access control vulnerability in Ceph where leaked inode references occur on writeback abort during umount, caused by failure to release wrbuffer claims, letting attackers cause inode eviction failure, exploit requires umount operation.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.17% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89646)

## Details

Type

Broken Access Control

Impact

Denial Of Service, Broken Access Control

CVSS vector

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

Published

11 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version containing the fix for leaked inode reference on writeback abort at umount.

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-2026-89646](https://nvd.nist.gov/vuln/detail/CVE-2026-89646)
- [https://git.kernel.org/stable/c/c25aee9c630fb86f98d79eccb75765067079b972](https://git.kernel.org/stable/c/c25aee9c630fb86f98d79eccb75765067079b972)
- [https://git.kernel.org/stable/c/ec32015a955c5d326c5e26610edfdcccd52f2314](https://git.kernel.org/stable/c/ec32015a955c5d326c5e26610edfdcccd52f2314)
- [https://git.kernel.org/stable/c/ac7a5a5385762df458d10cccc086a4e079be7409](https://git.kernel.org/stable/c/ac7a5a5385762df458d10cccc086a4e079be7409)

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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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