CVE-2026-64593

Kernel crash via stale reappeared-device state

Published Aug 6, 2026 · Updated Aug 6, 2026

A NULL pointer dereference in affected Linux Btrfs kernels allows local users with administrative storage access to crash the kernel via FITRIM. device_list_add() clears the missing-device flag after a device reappears but leaves its block-device pointer null; btrfs_trim_free_extents_throttle() then dereferences it during discard sizing. Triggering requires a degraded multi-device Btrfs filesystem, device rescanning, and a privileged FITRIM operation; the reported consequence is a kernel crash.

CVSS severity4.1
Medium
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

A NULL pointer dereference in affected Linux Btrfs kernels allows local users with administrative storage access to crash the kernel via FITRIM. device_list_add() clears the missing-device flag after a device reappears but leaves its block-device pointer null; btrfs_trim_free_extents_throttle() then dereferences it during discard sizing. Triggering requires a degraded multi-device Btrfs filesystem, device rescanning, and a privileged FITRIM operation; the reported consequence is a kernel crash.

The record

CVE
CVE-2026-64593
Published
Aug 6, 2026
Updated
Aug 6, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Aug 6, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 6, 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=4.3
  2. Affected versionversion=499f377f49f085ee4aa214c738e948e88626f39b <02c903fc6fc7e16c5d1f22d18784f1208acf43e3
  3. Affected versionversion=499f377f49f085ee4aa214c738e948e88626f39b <1b1937eb08f51319bf71575484cde2b8c517aedc
  4. Affected versionversion=499f377f49f085ee4aa214c738e948e88626f39b <210af872eafa0cf572a84cb303c0f9d2914c1226
  5. Affected versionversion=499f377f49f085ee4aa214c738e948e88626f39b <3d8fa4b828a86b33c60858e58aaab6df273ede05
  6. Affected versionversion=499f377f49f085ee4aa214c738e948e88626f39b <7a64521802997257b144e6edfb4e278dbeb972dd
  7. Affected versionversion=499f377f49f085ee4aa214c738e948e88626f39b <9c894159c5b8adc84072e3af0e55b0473a69564e
  8. Affected versionversion=499f377f49f085ee4aa214c738e948e88626f39b <b4af31b898a948e29861cb0bae734058f9a49d9b
  9. Affected versionversion=499f377f49f085ee4aa214c738e948e88626f39b <f41ae7e6664f3c4361129728f2c4d5f3ed995251

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

The Linux Kernel Organization · Linuxversion=4.3; version=499f377f49f085ee4aa214c738e948e88626f39b <02c903fc6fc7e16c5d1f22d18784f1208acf43e3; version=499f377f49f085ee4aa214c738e948e88626f39b <1b1937eb08f51319bf71575484cde2b8c517aedc; version=499f377f49f085ee4aa214c738e948e88626f39b <210af872eafa0cf572a84cb303c0f9d2914c1226; version=499f377f49f085ee4aa214c738e948e88626f39b <3d8fa4b828a86b33c60858e58aaab6df273ede05; version=499f377f49f085ee4aa214c738e948e88626f39b <7a64521802997257b144e6edfb4e278dbeb972dd; version=499f377f49f085ee4aa214c738e948e88626f39b <9c894159c5b8adc84072e3af0e55b0473a69564e; version=499f377f49f085ee4aa214c738e948e88626f39b <b4af31b898a948e29861cb0bae734058f9a49d9b; version=499f377f49f085ee4aa214c738e948e88626f39b <f41ae7e6664f3c4361129728f2c4d5f3ed995251

Published CVSS scores

4.1Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:H/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
Privilegesadmin
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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