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CVE-2026-31446 Linux CVE debrief

A use-after-free vulnerability was found in the Linux kernel, specifically in the ext4 filesystem. The vulnerability occurs when racing with umount, leading to a potential use-after-free in update_super_work. This could allow an attacker to execute arbitrary code or cause a denial of service. The fix involves modifying ext4_notify_error_sysfs() to detect if sysfs has already been torn down and skip the sysfs_notify() call in that case. A dedicated mutex (s_error_notify_mutex) serializes ext4_notify_error_sysfs() against kobject_del() in ext4_unregister_sysfs() to prevent TOCTOU races. System administrators and users of Linux-based systems should be aware of this vulnerability.

Vendor
Linux
Product
Unknown
CVSS
HIGH 7.8
CISA KEV
Not listed in stored evidence
Original CVE published
2026-04-22
Original CVE updated
2026-07-14
Advisory published
2026-04-22
Advisory updated
2026-07-14

Who should care

System administrators and users of Linux-based systems should be aware of this vulnerability, as it could potentially allow an attacker to gain elevated privileges or disrupt system operations. Linux kernel developers and maintainers should also be aware of this vulnerability and take necessary steps to address it.

Technical summary

The vulnerability is caused by a use-after-free in update_super_work when racing with umount. The fix involves modifying ext4_notify_error_sysfs() to detect if sysfs has already been torn down and skip the sysfs_notify() call in that case. A dedicated mutex (s_error_notify_mutex) serializes ext4_notify_error_sysfs() against kobject_del() in ext4_unregister_sysfs() to prevent TOCTOU races. This vulnerability affects Linux kernel versions and could potentially allow an attacker to execute arbitrary code or cause a denial of service.

Defensive priority

High

Recommended defensive actions

  • Apply patches from Linux kernel maintainers
  • Monitor system logs for suspicious activity
  • Implement compensating controls, such as SELinux or AppArmor
  • Regularly update Linux kernel to latest version
  • Use secure boot mechanisms to prevent loading of malicious modules
  • Review system configurations for potential vulnerabilities
  • Conduct regular vulnerability assessments

Evidence notes

The CVE record was published on 2026-04-22T14:16:38.340Z and was last modified on 2026-07-14T13:18:41.593Z. The NVD entry is currently Modified. This vulnerability affects Linux kernel versions and could potentially allow an attacker to execute arbitrary code or cause a denial of service. Evidence is limited, and defenders should verify affected scope and vendor guidance.

Official resources

AI-assisted PatchSiren debrief based on the supplied source corpus. The CVE record was published on 2026-04-22T14:16:38.340Z and has not been modified since then. The NVD entry is currently Modified.