---
title: "CVE-2026-89657: Linux Kernel libceph - Denial of Service"
description: "Linux kernel libceph contains a denial of service caused by improper validation of OSD extent maps in osd_sparse_read(), letting malicious authenticated Ceph OSD peers crash kernel Ceph clients via malformed sparse-read replies, exploit requires authenticated malicious OSD peer."
url: https://panop.io/threat-heartbeat/CVE-2026-89657/
---

# CVE-2026-89657 Linux Kernel libceph - Denial of Service

Linux kernel libceph contains a denial of service caused by improper validation of OSD extent maps in osd\_sparse\_read(), letting malicious authenticated Ceph OSD peers crash kernel Ceph clients via malformed sparse-read replies, exploit requires authenticated malicious OSD peer.

CVSS base score 7.5 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.61% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89657)

## 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 sparse extent map validation.

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-2026-89657](https://nvd.nist.gov/vuln/detail/CVE-2026-89657)
- [https://git.kernel.org/stable/c/94ae5145c520618802b0a24c047dcd5f05835db8](https://git.kernel.org/stable/c/94ae5145c520618802b0a24c047dcd5f05835db8)
- [https://git.kernel.org/stable/c/058ffa81f9440c5b4714685611cf697fd3739ec9](https://git.kernel.org/stable/c/058ffa81f9440c5b4714685611cf697fd3739ec9)
- [https://git.kernel.org/stable/c/201db408872ca12cf09e36bf0f560138c3dcfa1c](https://git.kernel.org/stable/c/201db408872ca12cf09e36bf0f560138c3dcfa1c)
- [https://git.kernel.org/stable/c/2571b35883268a266554e80d368e67fdfea7fb9d](https://git.kernel.org/stable/c/2571b35883268a266554e80d368e67fdfea7fb9d)
- [https://git.kernel.org/stable/c/9ec08b7499a62c6d4afa93d36ab47a43fcad57d1](https://git.kernel.org/stable/c/9ec08b7499a62c6d4afa93d36ab47a43fcad57d1)

[← All CVEs](https://panop.io/threat-heartbeat/)

## 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.

[Book a demo](https://panop.io/demo)