---
title: "CVE-2026-89720: Linux Kernel - Out-of-Bounds Read"
description: "Linux kernel contains an out-of-bounds read vulnerability in ubifs due to incorrect bounds check in ubifs_sb_verify_signature(), letting attackers with crafted signed UBIFS images cause memory read beyond allocation, exploit requires crafted UBIFS image."
url: https://panop.io/threat-heartbeat/CVE-2026-89720/
---

# CVE-2026-89720 Linux Kernel - Out-of-Bounds Read

Linux kernel contains an out-of-bounds read vulnerability in ubifs due to incorrect bounds check in ubifs\_sb\_verify\_signature(), letting attackers with crafted signed UBIFS images cause memory read beyond allocation, exploit requires crafted UBIFS image.

CVSS base score 7.7 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

EPSS

0.18% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-89720)

## Details

Type

Out-of-Bounds Read

Impact

Information Disclosure, Denial Of Service

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/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 ubifs signature length check.

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-2026-89720](https://nvd.nist.gov/vuln/detail/CVE-2026-89720)
- [https://git.kernel.org/stable/c/11abc34698cb3172badf8aa12e623f1bac98bbd8](https://git.kernel.org/stable/c/11abc34698cb3172badf8aa12e623f1bac98bbd8)
- [https://git.kernel.org/stable/c/37a9d25a563f5f9103282954ce573c4a61321e7c](https://git.kernel.org/stable/c/37a9d25a563f5f9103282954ce573c4a61321e7c)
- [https://git.kernel.org/stable/c/8cc3da72cf57acb4b77442ea8cec48425dff7c06](https://git.kernel.org/stable/c/8cc3da72cf57acb4b77442ea8cec48425dff7c06)
- [https://git.kernel.org/stable/c/ab7405bd86331cc2dbc8201699d4adc33bea75e7](https://git.kernel.org/stable/c/ab7405bd86331cc2dbc8201699d4adc33bea75e7)
- [https://git.kernel.org/stable/c/83e1aa9f5f906c9b1f4949d0521f0f950a159d96](https://git.kernel.org/stable/c/83e1aa9f5f906c9b1f4949d0521f0f950a159d96)
- [https://git.kernel.org/stable/c/95d27c1708bb6e8823c8e7c623f9abc2a91bf4bf](https://git.kernel.org/stable/c/95d27c1708bb6e8823c8e7c623f9abc2a91bf4bf)
- [https://git.kernel.org/stable/c/a1dc246f98bb94233effa4fa3ec7bf84700bb7d1](https://git.kernel.org/stable/c/a1dc246f98bb94233effa4fa3ec7bf84700bb7d1)
- [https://git.kernel.org/stable/c/f76b79d6e42af20682495bccd22f72c7164b0018](https://git.kernel.org/stable/c/f76b79d6e42af20682495bccd22f72c7164b0018)

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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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