CVE-2021-47214

5.5 MEDIUM 0.2% exploit odds Fix listed

What it is

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.

At a glance

Exploitability: Can be exploited locally on the machine with a low-privilege account. High risk of service disruption.
Exploit odds: 0.2% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2024-04-10 19:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-06-17 04:16 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.2% in the next 30 days (EPSS).
Severity: 5.5 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2024-04-10 19:15 UTC
Last modified: 2026-06-17 04:16 UTC
Exploit probability: 0.2% · EPSS, next 30 days
Weakness: CWE-401
Record status: Analyzed

Affected

Linux Kernel < 5.15.5
Linux Kernel 5.13.13
Linux Kernel 5.16

Attack profile CVSS 3.1 · 5.5

Attack vector: Local
Complexity: Low
Privileges needed: Low
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Raw vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2021-47214.md and follow it. Check whether this project is affected by CVE-2021-47214. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record