CVE-2022-50021

Kernel crash via post-validation block adjustment

Published Jun 18, 2025 · Updated May 11, 2026

Improper block validation in Linux ext4 allows local users to crash the kernel by mounting a corrupted bigalloc filesystem. ext4_free_blocks validates a block range before bigalloc adjustments, then passes the changed range to ext4_mb_clear_bb without revalidation. Exploitation requires privileges to mount a crafted or corrupted ext4 bigalloc filesystem; reaching the invalid range triggers a kernel BUG and service interruption.

CVSS severity7.8
High
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper block validation in Linux ext4 allows local users to crash the kernel by mounting a corrupted bigalloc filesystem. ext4_free_blocks validates a block range before bigalloc adjustments, then passes the changed range to ext4_mb_clear_bb without revalidation. Exploitation requires privileges to mount a crafted or corrupted ext4 bigalloc filesystem; reaching the invalid range triggers a kernel BUG and service interruption.

The record

CVE
CVE-2022-50021
Published
Jun 18, 2025
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 18, 2025CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=3.2
  2. Affected versionversion=84130193e0e6568dfdfb823f0e1e19aec80aff6e <1e1c2b86ef86a8477fd9b9a4f48a6bfe235606f6
  3. Affected versionversion=84130193e0e6568dfdfb823f0e1e19aec80aff6e <560a2744cbbf03cac65a6394f9b0d99aa437c867
  4. Affected versionversion=84130193e0e6568dfdfb823f0e1e19aec80aff6e <7550aade978371ac582f6d43b14c4cb89ca54463
  5. Affected versionversion=84130193e0e6568dfdfb823f0e1e19aec80aff6e <a2522041d248a8c969cbbc97e1fc2cd8b4de120d

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=3.2; version=84130193e0e6568dfdfb823f0e1e19aec80aff6e <1e1c2b86ef86a8477fd9b9a4f48a6bfe235606f6; version=84130193e0e6568dfdfb823f0e1e19aec80aff6e <560a2744cbbf03cac65a6394f9b0d99aa437c867; version=84130193e0e6568dfdfb823f0e1e19aec80aff6e <7550aade978371ac582f6d43b14c4cb89ca54463; version=84130193e0e6568dfdfb823f0e1e19aec80aff6e <a2522041d248a8c969cbbc97e1fc2cd8b4de120d

Published CVSS scores

7.8CanonicalCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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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