CVE-2026-31447Public exploit

Kernel memory corruption via unsupported ext4 geometry

Published Apr 22, 2026 · Updated Apr 22, 2026

Use-after-free in the ext4 filesystem in Linux Kernel allows attackers to corrupt kernel memory via a crafted filesystem image. __ext4_fill_super accepts an unsupported bigalloc superblock with a nonzero s_first_data_block, after which extent removal applies invalid cluster arithmetic and accesses freed memory. Exploitation requires a victim or privileged automounter to mount the image and perform an operation such as unlink or truncate, enabling a kernel crash, information disclosure, or filesystem and kernel-memory corruption.

CVSS severity7.8
High
EPSS probability0.14%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in the ext4 filesystem in Linux Kernel allows attackers to corrupt kernel memory via a crafted filesystem image. __ext4_fill_super accepts an unsupported bigalloc superblock with a nonzero s_first_data_block, after which extent removal applies invalid cluster arithmetic and accesses freed memory. Exploitation requires a victim or privileged automounter to mount the image and perform an operation such as unlink or truncate, enabling a kernel crash, information disclosure, or filesystem and kernel-memory corruption.

The record

CVE
CVE-2026-31447
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3822743dc20386d9897e999dbb990befa3a5b3f8
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3a926957cc95899ef88529710836edadc03c71a1
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5ad6d994255e27a3254079dfb50ca861fc31f2d0
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <7b58c110b4e1f028eb38eec9ed3555e9be81c8b0
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <7d5b04290156c3fc316eecc86a4f9d201ab7d44a
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ad1f6d608f33f59d21a3d025615d6786a6443998
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b77de3fceafbb39f30e4ff5dc986f863d5456417
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d787d3ae96648dc14a3b7ca8fde817177e82c1c7

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3822743dc20386d9897e999dbb990befa3a5b3f8; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3a926957cc95899ef88529710836edadc03c71a1; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <5ad6d994255e27a3254079dfb50ca861fc31f2d0; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <7b58c110b4e1f028eb38eec9ed3555e9be81c8b0; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <7d5b04290156c3fc316eecc86a4f9d201ab7d44a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ad1f6d608f33f59d21a3d025615d6786a6443998; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b77de3fceafbb39f30e4ff5dc986f863d5456417; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <d787d3ae96648dc14a3b7ca8fde817177e82c1c7

Published CVSS scores

7.8kernel.orgCVSS:3.1/AV:L/AC:L/PR:N/UI:R/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

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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