CVE-2026-23032

Local denial of service via configfs reference leak

Published Jan 31, 2026 · Updated Jan 31, 2026

Memory leak in the Linux Kernel null_blk driver allows local users to exhaust kernel memory through repeated nullb device removal. When a nullbX configfs group is removed, null_blk drops the parent group but fails to release references held for its timeout_inject, requeue_inject, and init_hctx_fault_inject children. Exploitation requires CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION and permission to create and remove nullb configfs groups; repeated removals accumulate unreclaimed kernel allocations and can interrupt service.

CVSS severity5.5
Medium
EPSS probability0.21%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Memory leak in the Linux Kernel null_blk driver allows local users to exhaust kernel memory through repeated nullb device removal. When a nullbX configfs group is removed, null_blk drops the parent group but fails to release references held for its timeout_inject, requeue_inject, and init_hctx_fault_inject children. Exploitation requires CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION and permission to create and remove nullb configfs groups; repeated removals accumulate unreclaimed kernel allocations and can interrupt service.

The record

CVE
CVE-2026-23032
Published
Jan 31, 2026
Updated
Jan 31, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Jan 31, 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=6.4
  2. Affected versionversion=bb4c19e030f45c5416f1eb4daa94fbaf7165e9ea <1a3286edf4d48ce37f8982ff3c3b65159a5ecbb2
  3. Affected versionversion=bb4c19e030f45c5416f1eb4daa94fbaf7165e9ea <40b94ec7edbbb867c4e26a1a43d2b898f04b93c5
  4. Affected versionversion=bb4c19e030f45c5416f1eb4daa94fbaf7165e9ea <d59ba448ccd595d5d65e197216cf781a87db2b28
  5. Affected versionversion=bb4c19e030f45c5416f1eb4daa94fbaf7165e9ea <f1718da051282698aa8fa150bebb9724f6389fda

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.4; version=bb4c19e030f45c5416f1eb4daa94fbaf7165e9ea <1a3286edf4d48ce37f8982ff3c3b65159a5ecbb2; version=bb4c19e030f45c5416f1eb4daa94fbaf7165e9ea <40b94ec7edbbb867c4e26a1a43d2b898f04b93c5; version=bb4c19e030f45c5416f1eb4daa94fbaf7165e9ea <d59ba448ccd595d5d65e197216cf781a87db2b28; version=bb4c19e030f45c5416f1eb4daa94fbaf7165e9ea <f1718da051282698aa8fa150bebb9724f6389fda

Published CVSS scores

5.5Amazon LinuxCVSS: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

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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

T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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