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Response snapshot Nov 5, 2026, 23:11 UTC

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VulnerabilityCVE-2026-31452

Linux kernel: ext4: convert inline data to extents when truncate exceeds inline size

In the Linux kernel, the following vulnerability has been resolved: ext4: convert inline data to extents when truncate exceeds inline size Add a check in ext4_setattr() to convert files from inline data storage to extent-based storage when truncate() grows the file size beyond the inline capacity.

At a glance

Exploited
Not known
Severity
7.8 High (CVSS 3.1)
Chance of exploitation
Not estimated
Sources
1 source

What to do

Check the vendor advisory for affected versions and fixes.

Read NVD CVE-2026-31452 (opens a new tab)

What happened

In the Linux kernel, the following vulnerability has been resolved:

ext4: convert inline data to extents when truncate exceeds inline size

Add a check in ext4_setattr() to convert files from inline data storage to extent-based storage when truncate() grows the file size beyond the inline capacity. This prevents the filesystem from entering an inconsistent state where the inline data flag is set but the file size exceeds what can be stored inline.

Without this fix, the following sequence causes a kernel BUG_ON():

Continue reading

1. Mount filesystem with inode that has inline flag set and small size 2. truncate(file, 50MB) - grows size but inline flag remains set 3. sendfile() attempts to write data 4. ext4_write_inline_data() hits BUG_ON(write_size > inline_capacity)

The crash occurs because ext4_write_inline_data() expects inline storage to accommodate the write, but the actual inline capacity (~60 bytes for i_block + ~96 bytes for xattrs) is far smaller than the file size and write request.

The fix checks if the new size from setattr exceeds the inode's actual inline capacity (EXT4_I(inode)->i_inline_size) and converts the file to extent-based storage before proceeding with the size change.

This addresses the root cause by ensuring the inline data flag and file size remain consistent during truncate operations.

Scores and how they were measured

CVSS base severity

7.8

Version 3.1As of

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Measurement source (opens a new tab)

How bad it is if exploited. Not a prediction of exploitation or proof you are exposed.

EPSS probability

Not available

A model's estimate of exploitation in the next 30 days, not certainty or your own risk.

Related technology

Sources

  1. Primary source

    NVD CVE-2026-31452 (opens a new tab)

    NVD record: description, CVSS (the CNA score is preferred), affected products, and publication date. Not evidence of exploitation.

    Published Checked

  2. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

  3. Primary source

    NVD CVE API 2.0 (opens a new tab)

    The NVD API page that supplied this CVE record.

    Published Date not suppliedChecked

Cite this record

For factual claims, cite the primary sources above; cite KEVWire for its compilation, dates, and classifications.

APA

KEVWire. (2026, November 5). Linux kernel: ext4: convert inline data to extents when truncate exceeds inline size (CVE-2026-31452). https://kevwire.com/record/CVE-2026-31452

MLA

"Linux kernel: ext4: convert inline data to extents when truncate exceeds inline size (CVE-2026-31452)." KEVWire, 5 Nov. 2026, kevwire.com/record/CVE-2026-31452.

Chicago

KEVWire. "Linux kernel: ext4: convert inline data to extents when truncate exceeds inline size (CVE-2026-31452)." Last modified November 5, 2026. https://kevwire.com/record/CVE-2026-31452.

Evidence summary (plain text)

Linux kernel: ext4: convert inline data to extents when truncate exceeds inline size (Apr 22, 2026).
In the Linux kernel, the following vulnerability has been resolved:

ext4: convert inline data to extents when truncate exceeds inline size

Add a check in ext4_setattr() to convert files from inline data storage
to extent-based storage when truncate() grows the file size beyond the
inline capacity. This prevents the filesystem from entering an
inconsistent state where the inline data flag is set but the file size
exceeds what can be stored inline.

Without this fix, the following sequence causes a kernel BUG_ON():

1. Mount filesystem with inode that has inline flag set and small size
2.
CVSS 7.8 (version 3.1; evidence as of Nov 5, 2026; https://nvd.nist.gov/vuln/detail/CVE-2026-31452).
Sources:
NVD CVE-2026-31452: https://nvd.nist.gov/vuln/detail/CVE-2026-31452
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-05T21:26:36.106Z&lastModEndDate=2026-11-05T23:10:57.358Z&resultsPerPage=500&startIndex=500
NVD CVE API 2.0: https://services.nvd.nist.gov/rest/json/cves/2.0?lastModStartDate=2026-11-05T20:51:23.450Z&lastModEndDate=2026-11-05T22:25:57.582Z&resultsPerPage=500&startIndex=1000
Record ID: CVE-2026-31452.
Record origin: Ingested record.
AI evidence: Not assessed.
Known exploitation: Not assessed.
Zero-day status: Not assessed. KEV membership alone does not establish zero-day status.
About this data

This record was ingested from a data source. Retrieved: Nov 5, 2026, 23:10 UTC. Ingestion is not an independent editorial investigation.

NVD status: Modified. Publication in the NVD is not evidence of exploitation.

A CISA KEV listing documents known exploitation, not necessarily a zero-day; absence from the catalog does not prove a vulnerability has never been exploited.

Technology tags indicate possible relevance, not verified exposure. Confirm the affected product, version, and configuration against your own inventory; KEVWire does not scan your systems.

A personal reading checklist on this device, not verified remediation.

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