CVE-2026-80548

Host kernel compromise via vfio-ccw race

Published Aug 26, 2026 · Updated Aug 27, 2026

Race conditions in the Linux s390 vfio_ccw subsystem allow local users with a VFIO device descriptor to corrupt host kernel memory. Concurrent channel I/O, device close or reset, and DMA unmap can run cp_free against related operations without full io_mutex coverage, causing use-after-free and double-free of channel-program structures. Exploitation requires IBM Z or LinuxONE with vfio-ccw passthrough configured; a guest or local VFIO client can read or write host kernel memory, crash the host, or hang it.

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

Race conditions in the Linux s390 vfio_ccw subsystem allow local users with a VFIO device descriptor to corrupt host kernel memory. Concurrent channel I/O, device close or reset, and DMA unmap can run cp_free against related operations without full io_mutex coverage, causing use-after-free and double-free of channel-program structures. Exploitation requires IBM Z or LinuxONE with vfio-ccw passthrough configured; a guest or local VFIO client can read or write host kernel memory, crash the host, or hang it.

The record

CVE
CVE-2026-80548
Published
Aug 26, 2026
Updated
Aug 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-366, 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=4f76617378ee97c557b526cb58d3c61eb0a9c963 <2a5ac0c0f1f7da33929211a2e41911bf72ee35d8
  2. Affected versionversion=4f76617378ee97c557b526cb58d3c61eb0a9c963 <2ba9efdf9ebedc4e54df4b56aa3b43a65f7967cd
  3. Affected versionversion=4f76617378ee97c557b526cb58d3c61eb0a9c963 <34f4feff3e90bd09308fad0974e97113b23b812a
  4. Affected versionversion=4f76617378ee97c557b526cb58d3c61eb0a9c963 <56d7488533ceac4e986e96e15c9e487a2245bc01
  5. Affected versionversion=4f76617378ee97c557b526cb58d3c61eb0a9c963 <b6aecea4b2b246f9fbd98a5712daa1193a60818e
  6. Affected versionversion=4f76617378ee97c557b526cb58d3c61eb0a9c963 <dab6a6627b0b0cce23653e99c7b0bf8c6cfd82e0
  7. Affected versionversion=4f76617378ee97c557b526cb58d3c61eb0a9c963 <f72a51810d49411bd8cad0c2df8592320a2fe5cc
  8. Affected versionversion=5.2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4f76617378ee97c557b526cb58d3c61eb0a9c963 <2a5ac0c0f1f7da33929211a2e41911bf72ee35d8; version=4f76617378ee97c557b526cb58d3c61eb0a9c963 <2ba9efdf9ebedc4e54df4b56aa3b43a65f7967cd; version=4f76617378ee97c557b526cb58d3c61eb0a9c963 <34f4feff3e90bd09308fad0974e97113b23b812a; version=4f76617378ee97c557b526cb58d3c61eb0a9c963 <56d7488533ceac4e986e96e15c9e487a2245bc01; version=4f76617378ee97c557b526cb58d3c61eb0a9c963 <b6aecea4b2b246f9fbd98a5712daa1193a60818e; version=4f76617378ee97c557b526cb58d3c61eb0a9c963 <dab6a6627b0b0cce23653e99c7b0bf8c6cfd82e0; version=4f76617378ee97c557b526cb58d3c61eb0a9c963 <f72a51810d49411bd8cad0c2df8592320a2fe5cc; version=5.2

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

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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-366Race Condition within a Thread
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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