CVE-2026-64244

Local denial of service via premature altmap assignment

Published Jul 24, 2026 · Updated Jul 24, 2026

Denial of service in affected Linux Kernel 6.6 and later releases allows local users to interrupt service after failed memory-block registration. __add_memory_block assigns mem->altmap before xa_store confirms registration, leaving the pointer set when error unwinding reaches memory_block_release. Exploitation requires local low-privileged access and an xa_store failure, such as under memory pressure; the resulting release path triggers a kernel WARN_ON.

CVSS severity5.5
Medium
EPSS probability0.11%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in affected Linux Kernel 6.6 and later releases allows local users to interrupt service after failed memory-block registration. __add_memory_block assigns mem->altmap before xa_store confirms registration, leaving the pointer set when error unwinding reaches memory_block_release. Exploitation requires local low-privileged access and an xa_store failure, such as under memory pressure; the resulting release path triggers a kernel WARN_ON.

The record

CVE
CVE-2026-64244
Published
Jul 24, 2026
Updated
Jul 24, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 24, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 24, 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=1a8c64e110435e44e71bcd50a75663174b575f22 <059ac6252a63edf1cea79bf30bd860a8c264b62c
  2. Affected versionversion=1a8c64e110435e44e71bcd50a75663174b575f22 <22dc0d042f02ce82aa61422ea5f232628bfd9e9c
  3. Affected versionversion=1a8c64e110435e44e71bcd50a75663174b575f22 <6c25bf4e44a2b6a14332f952bba0974521f5b72d
  4. Affected versionversion=1a8c64e110435e44e71bcd50a75663174b575f22 <802e113cf120df7208e4c7e604950a85e87120a8
  5. Affected versionversion=1a8c64e110435e44e71bcd50a75663174b575f22 <a2b8d7827f48ee54a686cb80e4a1d0ff954ec42a
  6. Affected versionversion=1a8c64e110435e44e71bcd50a75663174b575f22 <bc3dd82a0ffd488bb902f4c69c3d28fd4088d973
  7. Affected versionversion=6.6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1a8c64e110435e44e71bcd50a75663174b575f22 <059ac6252a63edf1cea79bf30bd860a8c264b62c; version=1a8c64e110435e44e71bcd50a75663174b575f22 <22dc0d042f02ce82aa61422ea5f232628bfd9e9c; version=1a8c64e110435e44e71bcd50a75663174b575f22 <6c25bf4e44a2b6a14332f952bba0974521f5b72d; version=1a8c64e110435e44e71bcd50a75663174b575f22 <802e113cf120df7208e4c7e604950a85e87120a8; version=1a8c64e110435e44e71bcd50a75663174b575f22 <a2b8d7827f48ee54a686cb80e4a1d0ff954ec42a; version=1a8c64e110435e44e71bcd50a75663174b575f22 <bc3dd82a0ffd488bb902f4c69c3d28fd4088d973; version=6.6

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

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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