Instituto Nacional de ciberseguridad. Sección Incibe
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CVE-2021-47491

Severity CVSS v4.0:
Pending analysis
Type:
Unavailable / Other
Publication date:
22/05/2024
Last modified:
29/09/2025

Description

In the Linux kernel, the following vulnerability has been resolved:<br /> <br /> mm: khugepaged: skip huge page collapse for special files<br /> <br /> The read-only THP for filesystems will collapse THP for files opened<br /> readonly and mapped with VM_EXEC. The intended usecase is to avoid TLB<br /> misses for large text segments. But it doesn&amp;#39;t restrict the file types<br /> so a THP could be collapsed for a non-regular file, for example, block<br /> device, if it is opened readonly and mapped with EXEC permission. This<br /> may cause bugs, like [1] and [2].<br /> <br /> This is definitely not the intended usecase, so just collapse THP for<br /> regular files in order to close the attack surface.<br /> <br /> [shy828301@gmail.com: fix vm_file check [3]]

Impact

Vector 3.x
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H CVSS v3.1 Severity and Metrics:

Base Score: 5.50 MEDIUM
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): None
Availability (A): High

Base Score 3.x
5.50
Severity 3.x
MEDIUM

Vulnerable products and versions

CPE From Up to
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* 5.4 (including) 5.10.78 (excluding)
cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* 5.11 (including) 5.14.16 (excluding)
cpe:2.3:o:linux:linux_kernel:5.15:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc6:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.15:rc7:*:*:*:*:*:*

To consult the complete list of CPE names with products and versions, see this page


References to Advisories, Solutions, and Tools