---
title: "CVE-2026-97991: Linux kernel vdpa_sim_blk - Out of Bounds Read & Write"
description: "Linux kernel vdpa_sim_blk contains an out-of-bounds read/write vulnerability caused by unsigned capacity subtraction underflow in vdpasim_blk_check_range(), letting attackers cause out-of-range buffer access, exploit requires crafted requests."
url: https://panop.io/threat-heartbeat/CVE-2026-97991/
---

# CVE-2026-97991 Linux kernel vdpa\_sim\_blk - Out of Bounds Read & Write

Linux kernel vdpa\_sim\_blk contains an out-of-bounds read/write vulnerability caused by unsigned capacity subtraction underflow in vdpasim\_blk\_check\_range(), letting attackers cause out-of-range buffer access, exploit requires crafted requests.

CVSS base score 7.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.12% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-97991)

## Details

Type

Out of Bounds Read

Impact

Denial Of Service, Data Tampering

CVSS vector

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Published

25 September 2026

Updated

15 October 2026

## Vendor fix

Update to the latest Linux kernel version containing the patch that rejects out-of-range sector starts.

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-2026-97991](https://nvd.nist.gov/vuln/detail/CVE-2026-97991)
- [https://git.kernel.org/stable/c/2ff2a8d063fdfa1e1479fb1fe2e3356a2ce89018](https://git.kernel.org/stable/c/2ff2a8d063fdfa1e1479fb1fe2e3356a2ce89018)
- [https://git.kernel.org/stable/c/36ef4d8527f71648f00347f6ba759f0b7e5e0977](https://git.kernel.org/stable/c/36ef4d8527f71648f00347f6ba759f0b7e5e0977)
- [https://git.kernel.org/stable/c/0a8693f00c408d85f086ad85d29e7030bf1e2055](https://git.kernel.org/stable/c/0a8693f00c408d85f086ad85d29e7030bf1e2055)
- [https://git.kernel.org/stable/c/14acb0d44b7d90a077beb7b92b444b90bafda9d9](https://git.kernel.org/stable/c/14acb0d44b7d90a077beb7b92b444b90bafda9d9)
- [https://git.kernel.org/stable/c/a8a1413a2cfdbedc896249f461d6d92efbbfe21f](https://git.kernel.org/stable/c/a8a1413a2cfdbedc896249f461d6d92efbbfe21f)
- [https://git.kernel.org/stable/c/d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf](https://git.kernel.org/stable/c/d6dac17e20fd2abd0eb8c09d69fccf7426e12bcf)
- [https://git.kernel.org/stable/c/000c6300776ceaf6b715780113f4275b1be4195b](https://git.kernel.org/stable/c/000c6300776ceaf6b715780113f4275b1be4195b)

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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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