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CVE-2021-47461— userfaultfd: fix a race between writeprotect and exit_mmap()

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writeprotect 和 exit_mmap() 之间存在竞争。

CVSS 7.8 · High EPSS 0.17% · P6

Affected Version Matrix 8

VendorProduct Version RangeStatus
Linux Linux 63b2d4174c4ad1f40b48d7138e71bcb564c1fe03< 3cda4bfffd4f755645577aaa9e96a606657b4525 affected
63b2d4174c4ad1f40b48d7138e71bcb564c1fe03< 149958ecd0627a9f1e9c678c25c665400054cd6a affected
63b2d4174c4ad1f40b48d7138e71bcb564c1fe03< cb185d5f1ebf900f4ae3bf84cee212e6dd035aca affected
5.7 affected
< 5.7 unaffected
5.10.76≤ 5.10.* unaffected
5.14.15≤ 5.14.* unaffected
5.15≤ * unaffected
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I. Basic Information for CVE-2021-47461

Vulnerability Information
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Vulnerability Title
userfaultfd: fix a race between writeprotect and exit_mmap()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: userfaultfd: fix a race between writeprotect and exit_mmap() A race is possible when a process exits, its VMAs are removed by exit_mmap() and at the same time userfaultfd_writeprotect() is called. The race was detected by KASAN on a development kernel, but it appears to be possible on vanilla kernels as well. Use mmget_not_zero() to prevent the race as done in other userfaultfd operations.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
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writeprotect 和 exit_mmap() 之间存在竞争。
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 63b2d4174c4ad1f40b48d7138e71bcb564c1fe03 ~ 3cda4bfffd4f755645577aaa9e96a606657b4525 -
Linux Linux 5.7 -

II. Public POCs for CVE-2021-47461

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III. Intelligence Information for CVE-2021-47461

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Other References for CVE-2021-47461 (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-2021-47459 7.8 HIGH can: j1939: j1939_netdev_start(): fix UAF for rx_kref of j1939_priv
CVE-2021-47483 7.8 HIGH regmap: Fix possible double-free in regcache_rbtree_exit()
CVE-2021-47485 7.8 HIGH IB/qib: Protect from buffer overflow in struct qib_user_sdma_pkt fields
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-2021-47451 7.8 HIGH netfilter: xt_IDLETIMER: fix panic that occurs when timer_type has garbage value
CVE-2021-47494 7.8 HIGH cfg80211: fix management registrations locking
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-2021-47448 7.5 HIGH mptcp: fix possible stall on recvmsg()
CVE-2021-47438 7.1 HIGH net/mlx5e: Fix memory leak in mlx5_core_destroy_cq() error path
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-2021-47477 comedi: dt9812: fix DMA buffers on stack
CVE-2021-47475 comedi: vmk80xx: fix transfer-buffer overflows
CVE-2021-47498 dm rq: don't queue request to blk-mq during DM suspend

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-2021-47461

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