CVE-2026-31781

Local service interruption via speculative function dispatch

Published May 1, 2026 · Updated May 1, 2026

Speculative execution in the DRM compat ioctl path in Linux Kernel allows local users to interrupt kernel availability via ioctl calls. drm_compat_ioctl uses a user-controlled value to index a function-pointer table without array_index_nospec(), enabling speculative dereference past the validated index. Reachability requires local access to a 32-bit compatibility DRM ioctl; the upstream record does not identify whether interruption manifests as a crash, hang, or reboot.

CVSS severity5.5
Medium
EPSS probability0.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Speculative execution in the DRM compat ioctl path in Linux Kernel allows local users to interrupt kernel availability via ioctl calls. drm_compat_ioctl uses a user-controlled value to index a function-pointer table without array_index_nospec(), enabling speculative dereference past the validated index. Reachability requires local access to a 32-bit compatibility DRM ioctl; the upstream record does not identify whether interruption manifests as a crash, hang, or reboot.

The record

CVE
CVE-2026-31781
Published
May 1, 2026
Updated
May 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 1, 2026CVE publishedPublication date reported by the CVE source.
  2. May 1, 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=00279b505289f7529d9be2e78915d0483ffbd314
  2. Affected versionversion=4.20
  3. Affected versionversion=505b5240329b922f21f91d5b5d1e535c805eca6d <27ef84bba9b9d7b03418c60fbc6069ea0e87b13c
  4. Affected versionversion=505b5240329b922f21f91d5b5d1e535c805eca6d <46a60ee8956ef1975f00455f614761c7ecedc09d
  5. Affected versionversion=505b5240329b922f21f91d5b5d1e535c805eca6d <489f2ef2b908898d01df697dc4fe1476674be640
  6. Affected versionversion=505b5240329b922f21f91d5b5d1e535c805eca6d <4a41c2b18fc05d30b718d2602cac339eae710b34
  7. Affected versionversion=505b5240329b922f21f91d5b5d1e535c805eca6d <5bb398991f378ef74d90b14a6ea8b61ff96cc03a
  8. Affected versionversion=505b5240329b922f21f91d5b5d1e535c805eca6d <d59c5d8539662d95887b4564f3f72ad38076a2d5
  9. Affected versionversion=505b5240329b922f21f91d5b5d1e535c805eca6d <f0e441be08a2eab10b2d06fccfa267ee599dd6b3
  10. Affected versionversion=505b5240329b922f21f91d5b5d1e535c805eca6d <f8995c2df519f382525ca4bc90553ad2ec611067
  11. Affected versionversion=7f3ebea19795eb38438cd3709fabf2afd53cf447
  12. Affected versionversion=a2a840d6dcae960c2dfdf3fcb1b759e1b7d90663
  13. Affected versionversion=abc60edcfc87771ff244763d4d19c67766f5dd0f
  14. Affected versionversion=d04e6ea0cec9e7d6cba806508f657d2d0dc6cacf

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=00279b505289f7529d9be2e78915d0483ffbd314; version=4.20; version=505b5240329b922f21f91d5b5d1e535c805eca6d <27ef84bba9b9d7b03418c60fbc6069ea0e87b13c; version=505b5240329b922f21f91d5b5d1e535c805eca6d <46a60ee8956ef1975f00455f614761c7ecedc09d; version=505b5240329b922f21f91d5b5d1e535c805eca6d <489f2ef2b908898d01df697dc4fe1476674be640; version=505b5240329b922f21f91d5b5d1e535c805eca6d <4a41c2b18fc05d30b718d2602cac339eae710b34; version=505b5240329b922f21f91d5b5d1e535c805eca6d <5bb398991f378ef74d90b14a6ea8b61ff96cc03a; version=505b5240329b922f21f91d5b5d1e535c805eca6d <d59c5d8539662d95887b4564f3f72ad38076a2d5; version=505b5240329b922f21f91d5b5d1e535c805eca6d <f0e441be08a2eab10b2d06fccfa267ee599dd6b3; version=505b5240329b922f21f91d5b5d1e535c805eca6d <f8995c2df519f382525ca4bc90553ad2ec611067; version=7f3ebea19795eb38438cd3709fabf2afd53cf447; version=a2a840d6dcae960c2dfdf3fcb1b759e1b7d90663; version=abc60edcfc87771ff244763d4d19c67766f5dd0f; version=d04e6ea0cec9e7d6cba806508f657d2d0dc6cacf

Published CVSS scores

5.5NIST NVDCVSS: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

No sourced classifications are available.

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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