Privilege Escalation Flaw in util-linux by The Linux Foundation

CVE-2026-76642

What is CVE-2026-76642?

Versions 2.41.5 and 2.42.2 of util-linux are vulnerable as they fail to verify the exit status of mount helpers before executing post-mount hooks. This oversight allows unprivileged users to exploit X-mount.idmap or X-mount.owner hooks, enabling them to clone filesystems with inherited SUID bits or improperly modify inode permissions after a helper process fails. This issue poses significant risks as attackers can perform unauthorized privileged operations on existing filesystems.

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