CVE-2026-72225

Journal abort via unsigned capacity underflow

Published Aug 15, 2026 · Updated Aug 15, 2026

Integer underflow in the Linux kernel's JBD2 layer allows local users to abort an ext4 journal via a crafted filesystem image. jbd2_journal_initialize_fast_commit() subtracts an attacker-controlled fast-commit block count from an unsigned journal limit before checking capacity, so an oversized count wraps and corrupts j_last, j_fc_first, and j_free. Triggering the flaw requires local access and permission to mount the image; the bounded consequence is journal abort 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

Integer underflow in the Linux kernel's JBD2 layer allows local users to abort an ext4 journal via a crafted filesystem image. jbd2_journal_initialize_fast_commit() subtracts an attacker-controlled fast-commit block count from an unsigned journal limit before checking capacity, so an oversized count wraps and corrupts j_last, j_fc_first, and j_free. Triggering the flaw requires local access and permission to mount the image; the bounded consequence is journal abort and service interruption.

The record

CVE
CVE-2026-72225
Published
Aug 15, 2026
Updated
Aug 15, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-191, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 15, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 15, 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=5.10
  2. Affected versionversion=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <289a2ca0c9b7eae74f93fc213b0b971669b8683d
  3. Affected versionversion=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9
  4. Affected versionversion=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6
  5. Affected versionversion=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <78955fdce8ff654e6d33a2fa90882a1e7eb26330
  6. Affected versionversion=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <a58fc10adf503969fec2007b5afe8987258046c4
  7. Affected versionversion=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <e144ad0250f77e23e28949587b8b57e40dc3b512
  8. Affected versionversion=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <fb9b49618ed7296ebfad62a3835da8945f727001

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.10; version=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <289a2ca0c9b7eae74f93fc213b0b971669b8683d; version=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <4450dcaadf7d4aae8b6e4223b5d6ee4eb77097a9; version=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <4b48dcb88bb9117e3d3f051175a9a8b7cff7f8b6; version=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <78955fdce8ff654e6d33a2fa90882a1e7eb26330; version=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <a58fc10adf503969fec2007b5afe8987258046c4; version=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <e144ad0250f77e23e28949587b8b57e40dc3b512; version=6866d7b3f2bb4f011041ba54c98b1584497fe2fd <fb9b49618ed7296ebfad62a3835da8945f727001

Published CVSS scores

5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
7.8Linux kernel CNACVSS: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

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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

CWE-191Integer Underflow (Wrap or Wraparound)
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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