CVE-2021-47000

Kernel-memory exhaustion via leaked Ceph inode references

Published Feb 28, 2024 · Updated May 23, 2026

An inode leak in the Ceph filesystem of affected Linux kernel versions allows local users to consume kernel memory through filehandle lookups. In fs/ceph/export.c, __fh_to_dentry returns after a failed getattr operation without dropping the inode reference it acquired. Reachability requires a mounted Ceph filesystem and a filehandle-to-dentry path, such as NFS export handling; repeated errors can reduce availability through accumulating kernel-memory use.

CVSS severity3.3
Low
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

An inode leak in the Ceph filesystem of affected Linux kernel versions allows local users to consume kernel memory through filehandle lookups. In fs/ceph/export.c, __fh_to_dentry returns after a failed getattr operation without dropping the inode reference it acquired. Reachability requires a mounted Ceph filesystem and a filehandle-to-dentry path, such as NFS export handling; repeated errors can reduce availability through accumulating kernel-memory use.

The record

CVE
CVE-2021-47000
Published
Feb 28, 2024
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.001
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 28, 2024CVE publishedPublication date reported by the CVE source.
  2. May 23, 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=10b7ddff50b3334414c0be4b6009671b18ba4845
  2. Affected versionversion=5.4.49 <5.4.120
  3. Affected versionversion=5.7.6 <5.8
  4. Affected versionversion=5.8
  5. Affected versionversion=807460787179dee5f74906965eeb5f3ca2353992 <2ad8af2b70e986284050213230428b823b950a38
  6. Affected versionversion=878dabb64117406abd40977b87544d05bb3031fc <0a219432127d396120fc88cabd82785e0ff72a2f
  7. Affected versionversion=878dabb64117406abd40977b87544d05bb3031fc <1775c7ddacfcea29051c67409087578f8f4d751b
  8. Affected versionversion=878dabb64117406abd40977b87544d05bb3031fc <22fa4c8288f1ec40f6d62d7a32c57ac176f9f0bc
  9. Affected versionversion=878dabb64117406abd40977b87544d05bb3031fc <bf45c9fe99aa8003d2703f1bd353f956dea47e40

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=10b7ddff50b3334414c0be4b6009671b18ba4845; version=5.4.49 <5.4.120; version=5.7.6 <5.8; version=5.8; version=807460787179dee5f74906965eeb5f3ca2353992 <2ad8af2b70e986284050213230428b823b950a38; version=878dabb64117406abd40977b87544d05bb3031fc <0a219432127d396120fc88cabd82785e0ff72a2f; version=878dabb64117406abd40977b87544d05bb3031fc <1775c7ddacfcea29051c67409087578f8f4d751b; version=878dabb64117406abd40977b87544d05bb3031fc <22fa4c8288f1ec40f6d62d7a32c57ac176f9f0bc; version=878dabb64117406abd40977b87544d05bb3031fc <bf45c9fe99aa8003d2703f1bd353f956dea47e40

Published CVSS scores

3.3CISA-ADPCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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

T1499.001OS Exhaustion Flood

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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