SB20261023174 - Improper control of a resource through its lifetime in Linux kernel fs

Description

This security bulletin contains information about 1 vulnerability.

1) Improper control of a resource through its lifetime (CVE-ID: CVE-2026-98996)

CWE-ID: CWE-664 - Improper control of a resource through its lifetime

CVSSv4: 1.8 [CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]

The vulnerability allows a local privileged user to cause mounts that are still in use to be detached, potentially disrupting filesystem access.

The vulnerability exists due to incomplete reference checks in the Linux kernel's propagate_mount_busy() function in fs/pnode.c when evaluating mounts affected by synchronous unmount propagation. A local privileged user can arrange nested copies of a shared mount tree inside a container and retain an open file descriptor to a copied tree to cause a subsequent host unmount to detach that tree despite its outstanding reference.

Remediation

Install update from vendor's website.

References

• https://git.kernel.org/stable/c/6857e209015f95be7a8f19a9cd5dac345b9b9859
• https://git.kernel.org/stable/c/a210ac218c307513d43e98a08f23c2dfbeeebc2f
• https://git.kernel.org/stable/c/bf2c8dec26fb792876b5e9bde7030c45d8be3908