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Linux Distros Unpatched Vulnerability : CVE-2021-47491
critical Nessus Plugin ID 230162
Synopsis
The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.Description
The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.- 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. [[email protected]: fix vm_file check [3]] (CVE-2021-47491)
Note that Nessus relies on the presence of the package as reported by the vendor.
Solution
There is no known solution at this time.Plugin Details
Severity: Critical
ID: 230162
File Name: unpatched_CVE_2021_47491.nasl
Version: 1.1
Type: local
Agent: unix
Family: Misc.
Published: 3/5/2025
Updated: 3/5/2025
Supported Sensors: Nessus Agent, Nessus
Risk Information
VPR
Risk Factor: Low
Score: 3.6
CVSS v2
Risk Factor: Critical
Base Score: 10
Temporal Score: 7.4
Vector: CVSS2#AV:N/AC:L/Au:N/C:C/I:C/A:C
CVSS Score Source: CVE-2021-47491
CVSS v3
Risk Factor: Critical
Base Score: 9.8
Temporal Score: 8.5
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C
Vulnerability Information
Required KB Items: Host/cpu, Host/local_checks_enabled, global_settings/vendor_unpatched
Exploit Ease: No known exploits are available
Vulnerability Publication Date: 7/21/2021
Reference Information
CVE: CVE-2021-47491