CVE-2021-47491 Affecting kernel-default package, versions <5.14.21-150400.24.122.2


Severity

Recommended
0.0
medium
0
10

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.05% (18th percentile)

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  • Snyk IDSNYK-SLES154-KERNELDEFAULT-7387334
  • published26 Jun 2024
  • disclosed25 Jun 2024

Introduced: 25 Jun 2024

CVE-2021-47491  (opens in a new tab)

How to fix?

Upgrade SLES:15.4 kernel-default to version 5.14.21-150400.24.122.2 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-default package and not the kernel-default package as distributed by SLES. See How to fix? for SLES:15.4 relevant fixed versions and status.

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

mm: khugepaged: skip huge page collapse for special files

The read-only THP for filesystems will collapse THP for files opened readonly and mapped with VM_EXEC. The intended usecase is to avoid TLB misses for large text segments. But it doesn't restrict the file types so a THP could be collapsed for a non-regular file, for example, block device, if it is opened readonly and mapped with EXEC permission. This may cause bugs, like [1] and [2].

This is definitely not the intended usecase, so just collapse THP for regular files in order to close the attack surface.

[shy828301@gmail.com: fix vm_file check [3]]

CVSS Scores

version 3.1