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EUVD-2026-309815

European Vulnerability Database identifier assigned by ENISA

Reserved

2026-10-02 07:10

Assigner

ENISA

Alias of

a CVE record, shown under related vulnerabilities. This identifier carries no description, severity or references of its own: they belong to that CVE.

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{
  "assigner": "ENISA",
  "date_reserved": "2026-10-02T07:10:36.580947+00:00",
  "id": "EUVD-2026-309815"
}

CVE-2021-47566 (GCVE-0-2021-47566)

Vulnerability from cvelistv5 – Published: 2024-05-24 15:12 – Updated: 2026-05-11 13:57

Title

proc/vmcore: fix clearing user buffer by properly using clear_user()

Summary

In the Linux kernel, the following vulnerability has been resolved: proc/vmcore: fix clearing user buffer by properly using clear_user() To clear a user buffer we cannot simply use memset, we have to use clear_user(). With a virtio-mem device that registers a vmcore_cb and has some logically unplugged memory inside an added Linux memory block, I can easily trigger a BUG by copying the vmcore via "cp": systemd[1]: Starting Kdump Vmcore Save Service... kdump[420]: Kdump is using the default log level(3). kdump[453]: saving to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/ kdump[458]: saving vmcore-dmesg.txt to /sysroot/var/crash/127.0.0.1-2021-11-11-14:59:22/ kdump[465]: saving vmcore-dmesg.txt complete kdump[467]: saving vmcore BUG: unable to handle page fault for address: 00007f2374e01000 #PF: supervisor write access in kernel mode #PF: error_code(0x0003) - permissions violation PGD 7a523067 P4D 7a523067 PUD 7a528067 PMD 7a525067 PTE 800000007048f867 Oops: 0003 [#1] PREEMPT SMP NOPTI CPU: 0 PID: 468 Comm: cp Not tainted 5.15.0+ #6 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.14.0-27-g64f37cc530f1-prebuilt.qemu.org 04/01/2014 RIP: 0010:read_from_oldmem.part.0.cold+0x1d/0x86 Code: ff ff ff e8 05 ff fe ff e9 b9 e9 7f ff 48 89 de 48 c7 c7 38 3b 60 82 e8 f1 fe fe ff 83 fd 08 72 3c 49 8d 7d 08 4c 89 e9 89 e8 <49> c7 45 00 00 00 00 00 49 c7 44 05 f8 00 00 00 00 48 83 e7 f81 RSP: 0018:ffffc9000073be08 EFLAGS: 00010212 RAX: 0000000000001000 RBX: 00000000002fd000 RCX: 00007f2374e01000 RDX: 0000000000000001 RSI: 00000000ffffdfff RDI: 00007f2374e01008 RBP: 0000000000001000 R08: 0000000000000000 R09: ffffc9000073bc50 R10: ffffc9000073bc48 R11: ffffffff829461a8 R12: 000000000000f000 R13: 00007f2374e01000 R14: 0000000000000000 R15: ffff88807bd421e8 FS: 00007f2374e12140(0000) GS:ffff88807f000000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2374e01000 CR3: 000000007a4aa000 CR4: 0000000000350eb0 Call Trace: read_vmcore+0x236/0x2c0 proc_reg_read+0x55/0xa0 vfs_read+0x95/0x190 ksys_read+0x4f/0xc0 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xae Some x86-64 CPUs have a CPU feature called "Supervisor Mode Access Prevention (SMAP)", which is used to detect wrong access from the kernel to user buffers like this: SMAP triggers a permissions violation on wrong access. In the x86-64 variant of clear_user(), SMAP is properly handled via clac()+stac(). To fix, properly use clear_user() when we're dealing with a user buffer.

Severity

No CVSS data available.

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2024-06-12 19:44 UTC

Assigner

Linux mitre root Scorecard

References

8 references

URL	Tags
https://git.kernel.org/stable/c/a9e164bd160be8cbe…
https://git.kernel.org/stable/c/33a7d698f30fa0b99…
https://git.kernel.org/stable/c/99d348b82bcb36171…
https://git.kernel.org/stable/c/9ef384ed300d1bcfb…
https://git.kernel.org/stable/c/fd7974c547abfb030…
https://git.kernel.org/stable/c/a8a917058faf4abae…
https://git.kernel.org/stable/c/7b3a34f08d11e7f05…
https://git.kernel.org/stable/c/c1e63117711977cc4…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < a9e164bd160be8cbee1df70acb379129e3cd2e7c (git) Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < 33a7d698f30fa0b99d50569e9909d3baa65d8f6a (git) Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < 99d348b82bcb36171f24411d3f1a15706a2a937a (git) Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < 9ef384ed300d1bcfb23d0ab0b487d544444d4b52 (git) Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < fd7974c547abfb03072a4ee706d3a6f182266f89 (git) Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < a8a917058faf4abaec9fb614bb6d5f8fe3529ec6 (git) Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < 7b3a34f08d11e7f05cd00b8e09adaa15192f0ad1 (git) Affected: 997c136f518c5debd63847e78e2a8694f56dcf90 , < c1e63117711977cc4295b2ce73de29dd17066c82 (git)
Linux	Linux	Affected: 3.0 Unaffected: 0 , < 3.0 (semver) Unaffected: 4.4.294 , ≤ 4.4.* (semver) Unaffected: 4.9.292 , ≤ 4.9.* (semver) Unaffected: 4.14.257 , ≤ 4.14.* (semver) Unaffected: 4.19.219 , ≤ 4.19.* (semver) Unaffected: 5.4.163 , ≤ 5.4.* (semver) Unaffected: 5.10.83 , ≤ 5.10.* (semver) Unaffected: 5.15.6 , ≤ 5.15.* (semver) Unaffected: 5.16 , ≤ * (original_commit_for_fix)

Show details on NVD website

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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.

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.

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EUVD-2026-309815

CVE-2021-47566 (GCVE-0-2021-47566)

Tags

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Nomenclature

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