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CVE-2021-47214— hugetlb, userfaultfd: fix reservation restore on userfaultfd error

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，该漏洞源于内存预留的恢复机制存在问题，可能导致内存泄漏。

AI Predicted 5.5 Difficulty: Easy EPSS 0.19% · P8

Possible ATT&CK Techniques 1 AI

T1564.004 · NTFS File Attributes

Affected Version Matrix 8

VendorProduct Version RangeStatus
Linux Linux c7b1850dfb41d0b4154aca8dbc04777fbd75616f< b5069d44e2fbc4a9093d005b3ef0949add3dd27e affected
c7b1850dfb41d0b4154aca8dbc04777fbd75616f< cc30042df6fcc82ea18acf0dace831503e60a0b7 affected
515b6124df6a84c957c5cc6bb6e8309dae7b1e9c affected
5.13.13< 5.14 affected
5.14 affected
< 5.14 unaffected
5.15.5≤ 5.15.* unaffected
5.16≤ * unaffected
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I. Basic Information for CVE-2021-47214

Vulnerability Information
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Vulnerability Title
hugetlb, userfaultfd: fix reservation restore on userfaultfd error
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: hugetlb, userfaultfd: fix reservation restore on userfaultfd error Currently in the is_continue case in hugetlb_mcopy_atomic_pte(), if we bail out using "goto out_release_unlock;" in the cases where idx >= size, or !huge_pte_none(), the code will detect that new_pagecache_page == false, and so call restore_reserve_on_error(). In this case I see restore_reserve_on_error() delete the reservation, and the following call to remove_inode_hugepages() will increment h->resv_hugepages causing a 100% reproducible leak. We should treat the is_continue case similar to adding a page into the pagecache and set new_pagecache_page to true, to indicate that there is no reservation to restore on the error path, and we need not call restore_reserve_on_error(). Rename new_pagecache_page to page_in_pagecache to make that clear.
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，该漏洞源于内存预留的恢复机制存在问题，可能导致内存泄漏。
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 c7b1850dfb41d0b4154aca8dbc04777fbd75616f ~ b5069d44e2fbc4a9093d005b3ef0949add3dd27e -
Linux Linux 5.14 -

II. Public POCs for CVE-2021-47214

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III. Intelligence Information for CVE-2021-47214

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Other References for CVE-2021-47214 (2)

Same Patch Batch · Linux · 2024-04-10 · 39 CVEs total

CVE-2021-47215 9.8 CRITICAL net/mlx5e: kTLS, Fix crash in RX resync flow
CVE-2021-47203 8.8 HIGH scsi: lpfc: Fix list_add() corruption in lpfc_drain_txq()
CVE-2021-47183 8.8 HIGH scsi: lpfc: Fix link down processing to address NULL pointer dereference
CVE-2021-47184 8.8 HIGH i40e: Fix NULL ptr dereference on VSI filter sync
CVE-2021-47201 7.8 HIGH iavf: free q_vectors before queues in iavf_disable_vf
CVE-2021-47200 7.8 HIGH drm/prime: Fix use after free in mmap with drm_gem_ttm_mmap
CVE-2024-26815 7.8 HIGH net/sched: taprio: proper TCA_TAPRIO_TC_ENTRY_INDEX check
CVE-2021-47197 7.8 HIGH net/mlx5e: nullify cq->dbg pointer in mlx5_debug_cq_remove()
CVE-2021-47188 7.8 HIGH scsi: ufs: core: Improve SCSI abort handling
CVE-2021-47189 7.8 HIGH btrfs: fix memory ordering between normal and ordered work functions
CVE-2021-47196 7.8 HIGH RDMA/core: Set send and receive CQ before forwarding to the driver
CVE-2021-47194 7.8 HIGH cfg80211: call cfg80211_stop_ap when switch from P2P_GO type
CVE-2021-47209 7.8 HIGH sched/fair: Prevent dead task groups from regaining cfs_rq's
CVE-2021-47191 7.1 HIGH scsi: scsi_debug: Fix out-of-bound read in resp_readcap16()
CVE-2021-47219 7.1 HIGH scsi: scsi_debug: Fix out-of-bound read in resp_report_tgtpgs()
CVE-2021-47210 usb: typec: tipd: Remove WARN_ON in tps6598x_block_read
CVE-2021-47198 scsi: lpfc: Fix use-after-free in lpfc_unreg_rpi() routine
CVE-2021-47207 ALSA: gus: fix null pointer dereference on pointer block
CVE-2021-47211 ALSA: usb-audio: fix null pointer dereference on pointer cs_desc
CVE-2021-47212 net/mlx5: Update error handler for UCTX and UMEM

Showing top 20 of 39 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2021-47214

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