CVE-2026-53343

Boot crash via unaligned KASAN shadow load

Published Jul 1, 2026 · Updated Jul 1, 2026

Availability flaw in the Linux kernel causes affected ARMv5 systems to crash during boot through an unaligned KASAN shadow-memory load. The ARM __switch_to() path uses the word-load instruction ldr on a byte-granular KASAN VMAP stack shadow address that is not guaranteed to be word aligned. The failure requires CONFIG_KASAN_VMALLOC and CONFIG_VMAP_STACK on an ARMv5 system; the resulting alignment exception occurs before init starts.

CVSS severity5.5
Medium
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

Availability flaw in the Linux kernel causes affected ARMv5 systems to crash during boot through an unaligned KASAN shadow-memory load. The ARM __switch_to() path uses the word-load instruction ldr on a byte-granular KASAN VMAP stack shadow address that is not guaranteed to be word aligned. The failure requires CONFIG_KASAN_VMALLOC and CONFIG_VMAP_STACK on an ARMv5 system; the resulting alignment exception occurs before init starts.

The record

CVE
CVE-2026-53343
Published
Jul 1, 2026
Updated
Jul 1, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 1, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 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=44e9a3bb76e5f2eecd374c8176b2c5163c8bb2e2 <2a4dc9a0ac3326e79fb58fdaae724b92127709a9
  2. Affected versionversion=44e9a3bb76e5f2eecd374c8176b2c5163c8bb2e2 <517720913bd3c17a52cd55a740064f68455ab88e
  3. Affected versionversion=44e9a3bb76e5f2eecd374c8176b2c5163c8bb2e2 <77a1f6883dc6e837bb2cb30b9b02e2f94338e2c6
  4. Affected versionversion=6.1.120 <6.1.176
  5. Affected versionversion=6.12.4 <6.12.94
  6. Affected versionversion=6.13
  7. Affected versionversion=6.6.64 <6.6.143
  8. Affected versionversion=8fe148d39c127de3fb78dfa6da95a3608dfda454 <c0b8c148a7754826156993ed6442d31536ec86b4
  9. Affected versionversion=c86d26b4b089ca294b3b7d915a7da61edb77935f <c74990828d3c486ee44aaa68240eb3abff289d1c
  10. Affected versionversion=ef21187c0672a2b2cbec44f33bab9ec47d5c277c <c2e3aadc8fef7da068490597fc5582f8f362aeb2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=44e9a3bb76e5f2eecd374c8176b2c5163c8bb2e2 <2a4dc9a0ac3326e79fb58fdaae724b92127709a9; version=44e9a3bb76e5f2eecd374c8176b2c5163c8bb2e2 <517720913bd3c17a52cd55a740064f68455ab88e; version=44e9a3bb76e5f2eecd374c8176b2c5163c8bb2e2 <77a1f6883dc6e837bb2cb30b9b02e2f94338e2c6; version=6.1.120 <6.1.176; version=6.12.4 <6.12.94; version=6.13; version=6.6.64 <6.6.143; version=8fe148d39c127de3fb78dfa6da95a3608dfda454 <c0b8c148a7754826156993ed6442d31536ec86b4; version=c86d26b4b089ca294b3b7d915a7da61edb77935f <c74990828d3c486ee44aaa68240eb3abff289d1c; version=ef21187c0672a2b2cbec44f33bab9ec47d5c277c <c2e3aadc8fef7da068490597fc5582f8f362aeb2

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

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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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