PT-2026-34351 · Linux · Linux Kernel

Published 2026-04-22 · Updated 2026-04-23 · CVE-2026-31446

Positive Technologies (AI Summary)

CVSS v3.1

7.8

High

Base vector

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

Name of the Vulnerable Software and Affected Versions Linux kernel (affected versions not specified)

Description A use-after-free issue exists in the ext4 file system during the unmount process. The problem occurs when update super work races with umount, specifically when ext4 notify error sysfs() calls sysfs notify(). This sequence accesses a kernfs node after it has been freed by kobject del() within the ext4 unregister sysfs() function.

Recommendations As a temporary workaround, restrict access to the /proc/fs/ext4/xx/mb groups interface to minimize the risk of triggering the race condition during unmount.

Fix

Use After Free

Weakness Enumeration

CWE-416

Related Identifiers

CVE-2026-31446

ECHO-3908-522A-C99B

Affected Products

Linux Kernel

References · 18

• https://osv.dev/vulnerability/BELL-CVE-2026-31446 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-31446 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-31446 · Security Note
• https://security-tracker.debian.org/tracker/CVE-2026-31446 · Vendor Advisory
• https://git.kernel.org/stable/c/d15e4b0a418537aafa56b2cb80d44add83e83697 · Patch
• https://git.kernel.org/stable/c/c4d829737329f2290dd41e290b7d75effdb2a7ff · Patch
• https://git.kernel.org/stable/c/c8fe17a1b308c3d8c703ebfb049b325f844342c3 · Patch
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-31446 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2026-31446 · Security Note
• https://git.kernel.org/stable/c/08b10e6f37fc533a759e9833af0692242e8b3f93 · Patch
• https://ubuntu.com/security/CVE-2026-31446 · Vendor Advisory
• https://git.kernel.org/stable/c/034053378dd81837fd6c7a43b37ee2e58d4f0b4e · Patch
• https://git.kernel.org/stable/c/9449f99ba04f5dd1c8423ad8a90b3651d7240d1d · Patch
• https://git.kernel.org/stable/c/c97e282f7bfd0c3554c63d289964a5ca6a1d2ffe · Patch
• https://twitter.com/infoflowcloud/status/2046981965664948449 · Twitter Post