Improper Preservation of Permissions Affecting kernel-modules-internal package, versions *


Severity

Recommended
medium

Based on CentOS security rating.

Threat Intelligence

EPSS
0.21% (11th percentile)

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  • Snyk IDSNYK-CENTOS8-KERNELMODULESINTERNAL-21038066
  • published16 Oct 2026
  • disclosed6 Oct 2026

Introduced: 6 Oct 2026

NewCVE-2026-98215  (opens in a new tab)
CWE-281  (opens in a new tab)

How to fix?

There is no fixed version for Centos:8 kernel-modules-internal.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-modules-internal package and not the kernel-modules-internal package as distributed by Centos. See How to fix? for Centos:8 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

selinux: preserve user SID across nested backing files

SELinux saves the user file SID in a backing-file security blob so it remains available after mmap() replaces vma->vm_file with a backing file.

For nested backing files (overlayfs over overlayfs, or FUSE passthrough backed by overlayfs), user_file may itself be a backing file. Its fsec->sid is the SID of the mounter that opened it, rather than the user that opened the top-level file. mprotect() then checks fd { use } against the mounter SID. This can incorrectly deny access without a domain transition, or check the wrong target SID after one.

Copy the saved user SID when user_file is a backing file. Keep using the regular file SID for the first backing layer.

With two nested overlayfs mounts and SELinux enforcing, mprotect(PROT_READ) returns EACCES with an fd { use } denial against the mounter SID. With this change, mprotect() succeeds.

Tested on arm64 QEMU with a small BusyBox initramfs and a purpose-built SELinux policy. The original test was also repeated with Fedora Cloud Base 44 userspace and gave the same result.

CVSS Base Scores

version 3.1