---
title: "CVE-2026-89654: Linux kernel ceph - Use After Free"
description: "Linux kernel ceph contains a use-after-free vulnerability in check_new_map() caused by missing reference counting on session objects during mutex unlock, letting concurrent threads access freed memory, exploit requires concurrent session teardown."
url: https://panop.io/threat-heartbeat/CVE-2026-89654/
---

# CVE-2026-89654 Linux kernel ceph - Use After Free

Linux kernel ceph contains a use-after-free vulnerability in check\_new\_map() caused by missing reference counting on session objects during mutex unlock, letting concurrent threads access freed memory, exploit requires concurrent session teardown.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

EPSS

0.55% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89654)

## Details

Type

Use After Free

Impact

Privilege Escalation

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/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 this issue.

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-2026-89654](https://nvd.nist.gov/vuln/detail/CVE-2026-89654)
- [https://git.kernel.org/stable/c/9646dfee880730aae4b379a4b8ee6c88ac735acd](https://git.kernel.org/stable/c/9646dfee880730aae4b379a4b8ee6c88ac735acd)
- [https://git.kernel.org/stable/c/21d5be092d947f8d83f76f7ebf3989e7e9230a98](https://git.kernel.org/stable/c/21d5be092d947f8d83f76f7ebf3989e7e9230a98)
- [https://git.kernel.org/stable/c/ee611a7509554c4ca1f54f6aefe592fb1df7ea70](https://git.kernel.org/stable/c/ee611a7509554c4ca1f54f6aefe592fb1df7ea70)

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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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