CVE-2026-43220

Service interruption via unlocked completion sequence allocation

Published May 6, 2026 · Updated May 6, 2026

Race condition in AMD IOMMU code in Linux Kernel 6.6.128 through 6.6.139 and 6.12.75 through 6.12.87 allows local users to interrupt service. The command path increments cmd_sem_val outside iommu->lock, letting concurrent invalidations queue CMD_COMPL_WAIT entries out of sequence and violate wait_on_sem() ordering. A low-privileged local user must induce concurrent TLB invalidations on a system using the AMD IOMMU; the reported consequence is completion-wait timeout and availability loss.

CVSS severity5.5
Medium
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 condition in AMD IOMMU code in Linux Kernel 6.6.128 through 6.6.139 and 6.12.75 through 6.12.87 allows local users to interrupt service. The command path increments cmd_sem_val outside iommu->lock, letting concurrent invalidations queue CMD_COMPL_WAIT entries out of sequence and violate wait_on_sem() ordering. A low-privileged local user must induce concurrent TLB invalidations on a system using the AMD IOMMU; the reported consequence is completion-wait timeout and availability loss.

The record

CVE
CVE-2026-43220
Published
May 6, 2026
Updated
May 6, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 6, 2026CVE publishedPublication date reported by the CVE source.
  2. May 6, 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=496269d12072ecb219826485bdbec70c92a8eef5 <48caa7542a795c9679ec1bd1bc2592e05a7369a4
  2. Affected versionversion=715c263119fd1b918a9fcbd8a36ea5b604a46324
  3. Affected versionversion=d2a0cac10597068567d336e85fa3cbdbe8ca62bf <9e249c48412828e807afddc21527eb734dc9bd3d
  4. Affected versionversion=e15768e68820142077bbca402d8e902f64ade1b0 <5000ce7fcb31067566a1a1a2e5b5bbff93625242
  5. Affected versionversion=f2f65b28d802a667119147444ec2ae33eebf9a58

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=496269d12072ecb219826485bdbec70c92a8eef5 <48caa7542a795c9679ec1bd1bc2592e05a7369a4; version=715c263119fd1b918a9fcbd8a36ea5b604a46324; version=d2a0cac10597068567d336e85fa3cbdbe8ca62bf <9e249c48412828e807afddc21527eb734dc9bd3d; version=e15768e68820142077bbca402d8e902f64ade1b0 <5000ce7fcb31067566a1a1a2e5b5bbff93625242; version=f2f65b28d802a667119147444ec2ae33eebf9a58

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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

T1499.004Application or System Exploitation

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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