Mount Rejection Vulnerability in Linux ext4 bigalloc Feature

Publication date: 2026-04-22

Last updated on: 2026-05-07

Assigner: kernel.org

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: reject mount if bigalloc with s_first_data_block != 0 bigalloc with s_first_data_block != 0 is not supported, reject mounting it.

CVSS Scores

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Meta Information

Published

2026-04-22

Last Modified

2026-05-07

Generated

2026-07-06

AI Q&A

2026-04-22

EPSS Evaluated

2026-07-05

NVD

CVE-2026-31447

EUVD

EUVD-2026-24782

Affected Vendors & Products

Vendor	Product	Version / Range
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	7.0
linux	linux_kernel	From 5.11 (inc) to 5.15.203 (exc)
linux	linux_kernel	From 5.16 (inc) to 6.1.168 (exc)
linux	linux_kernel	From 6.13 (inc) to 6.18.21 (exc)
linux	linux_kernel	From 6.19 (inc) to 6.19.11 (exc)
linux	linux_kernel	From 6.2 (inc) to 6.6.131 (exc)
linux	linux_kernel	From 6.7 (inc) to 6.12.80 (exc)
linux	linux_kernel	From 3.2 (inc) to 5.10.253 (exc)

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-UNKNOWN

Attack-Flow Graph

Executive Summary

This vulnerability relates to the Linux kernel's ext4 filesystem. Specifically, it involves the bigalloc feature combined with a non-zero s_first_data_block value. The issue is that bigalloc with s_first_data_block set to a value other than zero is not supported, which could lead to problems when mounting the filesystem. The vulnerability has been resolved by rejecting the mount operation if these conditions are detected.

Impact Analysis

If a filesystem using bigalloc with s_first_data_block not equal to zero is mounted, it could cause mounting failures or unexpected behavior in the Linux kernel. This could lead to system instability or data access issues, potentially impacting system reliability and availability.

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