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CVE-2021-47491— mm: khugepaged: skip huge page collapse for special files

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于文件系统的只读 THP 崩溃。

AI Predicted 5.3 Difficulty: Hard EPSS 0.21% · P10

Possible ATT&CK Techniques 1 AI

T1055 · Process Injection

Affected Version Matrix 8

VendorProduct Version RangeStatus
Linux Linux 99cb0dbd47a15d395bf3faa78dc122bc5efe3fc0< 6d67b2a73b8e3a079c355bab3c1aef7d85a044b8 affected
99cb0dbd47a15d395bf3faa78dc122bc5efe3fc0< 5fcb6fce74ffa614d964667110cf1a516c48c6d9 affected
99cb0dbd47a15d395bf3faa78dc122bc5efe3fc0< a4aeaa06d45e90f9b279f0b09de84bd00006e733 affected
5.4 affected
< 5.4 unaffected
5.10.78≤ 5.10.* unaffected
5.14.16≤ 5.14.* unaffected
5.15≤ * unaffected
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I. Basic Information for CVE-2021-47491

Vulnerability Information
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Vulnerability Title
mm: khugepaged: skip huge page collapse for special files
Source: CVE Program / CVE List V5
Vulnerability Description
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]]
Source: CVE Program / CVE List V5
CVSS Information
N/A
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于文件系统的只读 THP 崩溃。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 99cb0dbd47a15d395bf3faa78dc122bc5efe3fc0 ~ 6d67b2a73b8e3a079c355bab3c1aef7d85a044b8 -
Linux Linux 5.4 -

II. Public POCs for CVE-2021-47491

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III. Intelligence Information for CVE-2021-47491

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Other References for CVE-2021-47491 (3)

Same Patch Batch · Linux · 2024-05-22 · 63 CVEs total

CVE-2021-47496 9.8 CRITICAL net/tls: Fix flipped sign in tls_err_abort() calls
CVE-2021-47478 9.1 CRITICAL isofs: Fix out of bound access for corrupted isofs image
CVE-2021-47450 8.8 HIGH KVM: arm64: Fix host stage-2 PGD refcount
CVE-2021-47433 8.1 HIGH btrfs: fix abort logic in btrfs_replace_file_extents
CVE-2021-47451 7.8 HIGH netfilter: xt_IDLETIMER: fix panic that occurs when timer_type has garbage value
CVE-2021-47447 7.8 HIGH drm/msm/a3xx: fix error handling in a3xx_gpu_init()
CVE-2021-47446 7.8 HIGH drm/msm/a4xx: fix error handling in a4xx_gpu_init()
CVE-2021-47492 7.8 HIGH mm, thp: bail out early in collapse_file for writeback page
CVE-2021-47493 7.8 HIGH ocfs2: fix race between searching chunks and release journal_head from buffer_head
CVE-2021-47494 7.8 HIGH cfg80211: fix management registrations locking
CVE-2021-47485 7.8 HIGH IB/qib: Protect from buffer overflow in struct qib_user_sdma_pkt fields
CVE-2021-47483 7.8 HIGH regmap: Fix possible double-free in regcache_rbtree_exit()
CVE-2021-47461 7.8 HIGH userfaultfd: fix a race between writeprotect and exit_mmap()
CVE-2021-47459 7.8 HIGH can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv
CVE-2021-47448 7.5 HIGH mptcp: fix possible stall on recvmsg()
CVE-2021-47458 7.1 HIGH ocfs2: mount fails with buffer overflow in strlen
CVE-2021-47465 7.1 HIGH KVM: PPC: Book3S HV: Fix stack handling in idle_kvm_start_guest()
CVE-2021-47438 7.1 HIGH net/mlx5e: Fix memory leak in mlx5_core_destroy_cq() error path
CVE-2021-47473 scsi: qla2xxx: Fix a memory leak in an error path of qla2x00_process_els()
CVE-2021-47474 comedi: vmk80xx: fix bulk-buffer overflow

Showing top 20 of 63 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2021-47491

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