CVE-2026-53187

Memory disclosure and reboot via unchecked CPU ID

Published Jun 25, 2026 · Updated Jun 25, 2026

An out-of-bounds read in the RDMA DMAH allocator in Linux Kernel allows local users to disclose kernel memory or reboot the host. The allocator passes UVERBS_ATTR_ALLOC_DMAH_CPU_ID to cpumask_test_cpu() without checking it against nr_cpu_ids, so test_bit() indexes past the cpumask bitmap. Reboot requires CONFIG_DEBUG_PER_CPU_MAPS and panic_on_warn; other configurations expose an out-of-bounds kernel bitmap read.

CVSS severity7.1
High
EPSS probability0.16%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

An out-of-bounds read in the RDMA DMAH allocator in Linux Kernel allows local users to disclose kernel memory or reboot the host. The allocator passes UVERBS_ATTR_ALLOC_DMAH_CPU_ID to cpumask_test_cpu() without checking it against nr_cpu_ids, so test_bit() indexes past the cpumask bitmap. Reboot requires CONFIG_DEBUG_PER_CPU_MAPS and panic_on_warn; other configurations expose an out-of-bounds kernel bitmap read.

The record

CVE
CVE-2026-53187
Published
Jun 25, 2026
Updated
Jun 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-787, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 25, 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=6.17
  2. Affected versionversion=d83edab562a496a42720902a1d2effccd05c37c5 <0efbb6b54ff56300867027d8e0800d0e32226a20
  3. Affected versionversion=d83edab562a496a42720902a1d2effccd05c37c5 <323c98a4ff06aa28114f2bf658fb43eb3b536bbc
  4. Affected versionversion=d83edab562a496a42720902a1d2effccd05c37c5 <bd5e818be7964c1689fba2dad9e6bd3a827fee74

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=6.17; version=d83edab562a496a42720902a1d2effccd05c37c5 <0efbb6b54ff56300867027d8e0800d0e32226a20; version=d83edab562a496a42720902a1d2effccd05c37c5 <323c98a4ff06aa28114f2bf658fb43eb3b536bbc; version=d83edab562a496a42720902a1d2effccd05c37c5 <bd5e818be7964c1689fba2dad9e6bd3a827fee74

Published CVSS scores

7.1kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1499Endpoint Denial of Service

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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