CVE-2021-47214 (GCVE-0-2021-47214)
Vulnerability from cvelistv5 – Published: 2024-04-10 19:01 – Updated: 2026-05-23 15:19
VLAI
EPSS
VEX
Title
hugetlb, userfaultfd: fix reservation restore on userfaultfd error
Summary
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.
Severity
No CVSS data available.
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-04-12 16:35 UTC
Assigner
References
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
c7b1850dfb41d0b4154aca8dbc04777fbd75616f , < b5069d44e2fbc4a9093d005b3ef0949add3dd27e
(git)
Affected: c7b1850dfb41d0b4154aca8dbc04777fbd75616f , < cc30042df6fcc82ea18acf0dace831503e60a0b7 (git) Affected: 515b6124df6a84c957c5cc6bb6e8309dae7b1e9c (git) Affected: 5.13.13 , < 5.14 (semver) |
guessed | |
| Linux | Linux |
Affected:
5.14
Unaffected: 0 , < 5.14 (semver) Unaffected: 5.15.5 , ≤ 5.15.* (semver) Unaffected: 5.16 , ≤ * (original_commit_for_fix) |
guessed |
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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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