---
title: "CVE-2026-89635: Linux Kernel ksmbd - Use After Free"
description: "Linux kernel ksmbd contains a use-after-free vulnerability caused by rebinding oplocks of all detached durable handles on an inode to a reconnecting session instead of only the file's own, letting authenticated attackers cause kernel memory corruption during durable reconnects, exploit requires multiple sessions with durable handles on the same file."
url: https://panop.io/threat-heartbeat/CVE-2026-89635/
---

# CVE-2026-89635 Linux Kernel ksmbd - Use After Free

Linux kernel ksmbd contains a use-after-free vulnerability caused by rebinding oplocks of all detached durable handles on an inode to a reconnecting session instead of only the file's own, letting authenticated attackers cause kernel memory corruption during durable reconnects, exploit requires multiple sessions with durable handles on the same file.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.55% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89635)

## Details

Type

Use After Free

Impact

Denial Of Service, 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 ksmbd fix for durable reconnect oplock rebinding.

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-2026-89635](https://nvd.nist.gov/vuln/detail/CVE-2026-89635)
- [https://git.kernel.org/stable/c/3f220a0a62e6b9b391c9d1f0e6580b05173cc7f7](https://git.kernel.org/stable/c/3f220a0a62e6b9b391c9d1f0e6580b05173cc7f7)
- [https://git.kernel.org/stable/c/74e3ef4630f004c0de40c0540648a5a4033c6c9d](https://git.kernel.org/stable/c/74e3ef4630f004c0de40c0540648a5a4033c6c9d)

[← 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)