GHSA-8G2P-P68F-4WQR
Vulnerability from github – Published: 2024-05-22 09:31 – Updated: 2025-09-29 18:33In 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]]
{
"affected": [],
"aliases": [
"CVE-2021-47491"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-05-22T09:15:10Z",
"severity": "MODERATE"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nmm: khugepaged: skip huge page collapse for special files\n\nThe read-only THP for filesystems will collapse THP for files opened\nreadonly and mapped with VM_EXEC. The intended usecase is to avoid TLB\nmisses for large text segments. But it doesn\u0027t restrict the file types\nso a THP could be collapsed for a non-regular file, for example, block\ndevice, if it is opened readonly and mapped with EXEC permission. This\nmay cause bugs, like [1] and [2].\n\nThis is definitely not the intended usecase, so just collapse THP for\nregular files in order to close the attack surface.\n\n[shy828301@gmail.com: fix vm_file check [3]]",
"id": "GHSA-8g2p-p68f-4wqr",
"modified": "2025-09-29T18:33:07Z",
"published": "2024-05-22T09:31:46Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2021-47491"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/5fcb6fce74ffa614d964667110cf1a516c48c6d9"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/6d67b2a73b8e3a079c355bab3c1aef7d85a044b8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/a4aeaa06d45e90f9b279f0b09de84bd00006e733"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"type": "CVSS_V3"
}
]
}
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