CVE-2026-80552

Host compromise via unchecked VFIO region indexes

Published Aug 26, 2026 · Updated Aug 27, 2026

Out-of-bounds access in Linux s390/vfio_ccw allows local users with a delegated VFIO device to compromise the host kernel. The read, write, and VFIO_DEVICE_GET_REGION_INFO paths use a region array index derived from crafted operations without clamping it to the existing region count. An open vfio-ccw mediated-device descriptor on IBM Z or LinuxONE is required; crafted operations can disclose or corrupt host kernel memory or panic the host without separate user interaction.

CVSS severity8.8
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds access in Linux s390/vfio_ccw allows local users with a delegated VFIO device to compromise the host kernel. The read, write, and VFIO_DEVICE_GET_REGION_INFO paths use a region array index derived from crafted operations without clamping it to the existing region count. An open vfio-ccw mediated-device descriptor on IBM Z or LinuxONE is required; crafted operations can disclose or corrupt host kernel memory or panic the host without separate user interaction.

The record

CVE
CVE-2026-80552
Published
Aug 26, 2026
Updated
Aug 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-125, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 26, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.2
  2. Affected versionversion=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <3acbedf5c0b8e0971f0de423c05cc02bbf6ddb99
  3. Affected versionversion=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <649badf3a2fd8929e40198603a2cb21b74c21700
  4. Affected versionversion=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <79ea5e0c4c8a9842ae85f45062d947b3297dfc07
  5. Affected versionversion=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <988d9b5be3c2c4baf9457ce8e11b477e13eb9fcf
  6. Affected versionversion=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <9f5f9a78fedc45bc29d6a0a64e3a3472361afae5
  7. Affected versionversion=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <d3b1e38404b22df5a1f93019f2bb656feaad5ae3
  8. Affected versionversion=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <d597fa1273802941c7801202135976fecc29672b

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.2; version=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <3acbedf5c0b8e0971f0de423c05cc02bbf6ddb99; version=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <649badf3a2fd8929e40198603a2cb21b74c21700; version=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <79ea5e0c4c8a9842ae85f45062d947b3297dfc07; version=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <988d9b5be3c2c4baf9457ce8e11b477e13eb9fcf; version=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <9f5f9a78fedc45bc29d6a0a64e3a3472361afae5; version=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <d3b1e38404b22df5a1f93019f2bb656feaad5ae3; version=db8e5d17ac03a65e2e0ee0ba50bf61a99741d871 <d597fa1273802941c7801202135976fecc29672b

Published CVSS scores

8.8Linux Kernel CVE TeamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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