---
title: "CVE-2026-89648: Linux Kernel Ceph - Denial of Service"
description: "Linux kernel Ceph contains a denial of service caused by unbounded delegated inode count handling in ceph_parse_deleg_inos(), letting a malicious or compromised MDS cause resource exhaustion, exploit requires attacker to control MDS."
url: https://panop.io/threat-heartbeat/CVE-2026-89648/
---

# CVE-2026-89648 Linux Kernel Ceph - Denial of Service

Linux kernel Ceph contains a denial of service caused by unbounded delegated inode count handling in ceph\_parse\_deleg\_inos(), letting a malicious or compromised MDS cause resource exhaustion, exploit requires attacker to control MDS.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

EPSS

0.61% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89648)

## Details

Type

Denial of Service

Impact

Denial Of Service

CVSS vector

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

Published

11 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version containing the fix for delegated inode count capping.

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-2026-89648](https://nvd.nist.gov/vuln/detail/CVE-2026-89648)
- [https://git.kernel.org/stable/c/4bd3158bd62466d57ed72a3f7bc5f205fedd6919](https://git.kernel.org/stable/c/4bd3158bd62466d57ed72a3f7bc5f205fedd6919)
- [https://git.kernel.org/stable/c/c040e139f1a629b767f900bbbc3f9892c290ed85](https://git.kernel.org/stable/c/c040e139f1a629b767f900bbbc3f9892c290ed85)
- [https://git.kernel.org/stable/c/f341270ac5f5077804d7837ce77b0f0df1cea29d](https://git.kernel.org/stable/c/f341270ac5f5077804d7837ce77b0f0df1cea29d)

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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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