CVE-2026-43364

Local crash via unchecked ublk disk pointer

Published May 8, 2026 · Updated May 8, 2026

NULL pointer dereference in affected Linux Kernel releases allows local users to crash the system through a crafted ublk size update. ublk_ctrl_set_size() passes ub->ub_disk to set_capacity_and_notify() without confirming that the pointer exists after device addition or stop. A local user controlling an unprivileged ublk device can send UBLK_CMD_UPDATE_SIZE before start or after stop, dereferencing NULL and interrupting the host.

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

NULL pointer dereference in affected Linux Kernel releases allows local users to crash the system through a crafted ublk size update. ublk_ctrl_set_size() passes ub->ub_disk to set_capacity_and_notify() without confirming that the pointer exists after device addition or stop. A local user controlling an unprivileged ublk device can send UBLK_CMD_UPDATE_SIZE before start or after stop, dereferencing NULL and interrupting the host.

The record

CVE
CVE-2026-43364
Published
May 8, 2026
Updated
May 8, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-476, T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 8, 2026CVE publishedPublication date reported by the CVE source.
  2. May 8, 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=6.16
  2. Affected versionversion=98b995660bff011d8e00af03abd74ac7d1ac1390 <25966fc097691e5c925ad080f64a2f19c5fd940a
  3. Affected versionversion=98b995660bff011d8e00af03abd74ac7d1ac1390 <c28d945bfa92e15147e93b73f95345b9bec979b0
  4. Affected versionversion=98b995660bff011d8e00af03abd74ac7d1ac1390 <f13fe6794726755a43090cb680c4c58cea6aa5f1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.16; version=98b995660bff011d8e00af03abd74ac7d1ac1390 <25966fc097691e5c925ad080f64a2f19c5fd940a; version=98b995660bff011d8e00af03abd74ac7d1ac1390 <c28d945bfa92e15147e93b73f95345b9bec979b0; version=98b995660bff011d8e00af03abd74ac7d1ac1390 <f13fe6794726755a43090cb680c4c58cea6aa5f1

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

CWE-476NULL Pointer Dereference
T1499.004Endpoint Denial of Service: Application 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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