CVE-2021-47007

Kernel panic via unchecked F2FS shrink capacity

Published Feb 28, 2024 · Updated May 11, 2026

Denial of service in the Linux kernel F2FS resize path allows local users to trigger a kernel panic by shrinking a filesystem. f2fs_resize_fs() fails to verify that the smaller target has room for every valid and reserved block, so migration exhausts free segments in free_segment_range(). Reaching the fault requires local access and the ability to resize a sufficiently full mounted F2FS filesystem; the resulting panic interrupts the host.

CVSS severity5.5
Medium
EPSS probability0.24%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in the Linux kernel F2FS resize path allows local users to trigger a kernel panic by shrinking a filesystem. f2fs_resize_fs() fails to verify that the smaller target has room for every valid and reserved block, so migration exhausts free segments in free_segment_range(). Reaching the fault requires local access and the ability to resize a sufficiently full mounted F2FS filesystem; the resulting panic interrupts the host.

The record

CVE
CVE-2021-47007
Published
Feb 28, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-754, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 28, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.8
  2. Affected versionversion=b4b10061ef98c583bcf82a4200703fbaa98c18dc <1c20a4896409f5ca1c770e1880c33d0a28a8b10f
  3. Affected versionversion=b4b10061ef98c583bcf82a4200703fbaa98c18dc <3ab0598e6d860ef49d029943ba80f627c15c15d6
  4. Affected versionversion=b4b10061ef98c583bcf82a4200703fbaa98c18dc <822054e5026c43b1dd60cf387dd999e95ee2ecc2
  5. Affected versionversion=b4b10061ef98c583bcf82a4200703fbaa98c18dc <860afd680d9cc1dabd61cda3cd246f60aa1eb705

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.8; version=b4b10061ef98c583bcf82a4200703fbaa98c18dc <1c20a4896409f5ca1c770e1880c33d0a28a8b10f; version=b4b10061ef98c583bcf82a4200703fbaa98c18dc <3ab0598e6d860ef49d029943ba80f627c15c15d6; version=b4b10061ef98c583bcf82a4200703fbaa98c18dc <822054e5026c43b1dd60cf387dd999e95ee2ecc2; version=b4b10061ef98c583bcf82a4200703fbaa98c18dc <860afd680d9cc1dabd61cda3cd246f60aa1eb705

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-754Improper Check for Unusual or Exceptional Conditions
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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