CVE-2026-80553

Guest-to-host code execution via workqueue use-after-free

Published Aug 26, 2026 · Updated Aug 27, 2026

Use-after-free in Linux s390 vfio-ccw allows local users with delegated VFIO access to execute code in the host kernel. The release path frees the vfio_ccw_private structure without canceling io_work and crw_work, so deferred handlers dereference and modify reclaimed kernel memory. Reachability requires an IBM Z or LinuxONE host with vfio-ccw passthrough configured and control of the delegated VFIO device; the race can corrupt host-kernel memory or crash the host.

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

Use-after-free in Linux s390 vfio-ccw allows local users with delegated VFIO access to execute code in the host kernel. The release path frees the vfio_ccw_private structure without canceling io_work and crw_work, so deferred handlers dereference and modify reclaimed kernel memory. Reachability requires an IBM Z or LinuxONE host with vfio-ccw passthrough configured and control of the delegated VFIO device; the race can corrupt host-kernel memory or crash the host.

The record

CVE
CVE-2026-80553
Published
Aug 26, 2026
Updated
Aug 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-364, 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=4.12
  2. Affected versionversion=e5f84dbaea59b4f712dac428c337528b70e1c533 <7492ca2d0c5d59add01e267be9f5a6eeb8076fd7
  3. Affected versionversion=e5f84dbaea59b4f712dac428c337528b70e1c533 <77f5e888d2e607a0b3141fb95091ad6ef1cca9a2
  4. Affected versionversion=e5f84dbaea59b4f712dac428c337528b70e1c533 <79c60b2c61105368dcc8444eb45847e21734f7c4
  5. Affected versionversion=e5f84dbaea59b4f712dac428c337528b70e1c533 <87d569cb35a541b31a184faf982540694d4c9a89
  6. Affected versionversion=e5f84dbaea59b4f712dac428c337528b70e1c533 <b7ae0f7993867d009a4b554fc1d6d451c10580a0
  7. Affected versionversion=e5f84dbaea59b4f712dac428c337528b70e1c533 <b94b28c1f0fae53b2f2d6180ae6442c9a1558f67
  8. Affected versionversion=e5f84dbaea59b4f712dac428c337528b70e1c533 <dc47a98abe6714577a25224534dbd356051097a3
  9. Affected versionversion=e5f84dbaea59b4f712dac428c337528b70e1c533 <e868ea8be0bc88c6982f48ecf3259d98afd884ae

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=4.12; version=e5f84dbaea59b4f712dac428c337528b70e1c533 <7492ca2d0c5d59add01e267be9f5a6eeb8076fd7; version=e5f84dbaea59b4f712dac428c337528b70e1c533 <77f5e888d2e607a0b3141fb95091ad6ef1cca9a2; version=e5f84dbaea59b4f712dac428c337528b70e1c533 <79c60b2c61105368dcc8444eb45847e21734f7c4; version=e5f84dbaea59b4f712dac428c337528b70e1c533 <87d569cb35a541b31a184faf982540694d4c9a89; version=e5f84dbaea59b4f712dac428c337528b70e1c533 <b7ae0f7993867d009a4b554fc1d6d451c10580a0; version=e5f84dbaea59b4f712dac428c337528b70e1c533 <b94b28c1f0fae53b2f2d6180ae6442c9a1558f67; version=e5f84dbaea59b4f712dac428c337528b70e1c533 <dc47a98abe6714577a25224534dbd356051097a3; version=e5f84dbaea59b4f712dac428c337528b70e1c533 <e868ea8be0bc88c6982f48ecf3259d98afd884ae

Published CVSS scores

8.8LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
7.0Red HatCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/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-364Signal Handler Race Condition
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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