---
title: "CVE-2026-89551: Linux Kernel - Integer Overflow"
description: "Linux kernel contains an integer underflow vulnerability in SUNRPC xdr_buf_trim function caused by improper clamping of buf->len during subtraction, letting attackers cause buffer length miscalculation, exploit requires crafted input triggering xdr_buf_trim."
url: https://panop.io/threat-heartbeat/CVE-2026-89551/
---

# CVE-2026-89551 Linux Kernel - Integer Overflow

Linux kernel contains an integer underflow vulnerability in SUNRPC xdr\_buf\_trim function caused by improper clamping of buf->len during subtraction, letting attackers cause buffer length miscalculation, exploit requires crafted input triggering xdr\_buf\_trim.

CVSS base score 9.8 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.51% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89551)

## Details

Type

Integer Overflow

Impact

Denial Of Service

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 xdr\_buf\_trim underflow.

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-2026-89551](https://nvd.nist.gov/vuln/detail/CVE-2026-89551)
- [https://git.kernel.org/stable/c/e6267cccd7b05cc514e57f2160aa8db85f5c2701](https://git.kernel.org/stable/c/e6267cccd7b05cc514e57f2160aa8db85f5c2701)
- [https://git.kernel.org/stable/c/4bf59cb0ea5b0ddfbc46a1dc2fa78fc8b9986ce4](https://git.kernel.org/stable/c/4bf59cb0ea5b0ddfbc46a1dc2fa78fc8b9986ce4)
- [https://git.kernel.org/stable/c/a3d77bcd974b8625d16bddf448cb3a1b5e37049c](https://git.kernel.org/stable/c/a3d77bcd974b8625d16bddf448cb3a1b5e37049c)
- [https://git.kernel.org/stable/c/a924ac4c78afab71bf82641afa3b62e0c4a8b55e](https://git.kernel.org/stable/c/a924ac4c78afab71bf82641afa3b62e0c4a8b55e)
- [https://git.kernel.org/stable/c/fa16bbe987b47e771e52eeb1b4540f18d92496ac](https://git.kernel.org/stable/c/fa16bbe987b47e771e52eeb1b4540f18d92496ac)
- [https://git.kernel.org/stable/c/3f491306dcb673ff5e78e1044ba450c58978774e](https://git.kernel.org/stable/c/3f491306dcb673ff5e78e1044ba450c58978774e)
- [https://git.kernel.org/stable/c/85e9602650e9df07190abe817cee3b4d9bc3df17](https://git.kernel.org/stable/c/85e9602650e9df07190abe817cee3b4d9bc3df17)
- [https://git.kernel.org/stable/c/ad0cce80d4af2f74674e8b635d97aa3880e83da8](https://git.kernel.org/stable/c/ad0cce80d4af2f74674e8b635d97aa3880e83da8)

[← 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)