BlackTreeCVE Intelligence
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Full vulnerability report · 2022
CVE-2021-45868High confidence

In the Linux kernel before 5.15.3, fs/quota/quota_tree.c does not validate the block number in the quota tree (on disk)

n/a · n/a

5.5MediumCVSS 3.1
Recommended action
Within 7 days

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
Distribution package intelligence

Ubuntu vendor package status

Canonical’s release and source-package findings are shown separately from local repository availability.

1 package state
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Ubuntu releaseSource packageVendor stateFixed versionEvidence
Ubuntu 24.04 LTSnoble · standard archivelinux-raspi-realtimeAffected, no fix publishedCanonical OVAL identifies this running kernel flavour as affected and does not publish a fixed package version in this definition.Not published in this feedCanonical record ↗Source updated 11 Sept 2026
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Select the national-authority views to include. The exact source language is shown on each matched advisory. Your choice is remembered on this device and encoded in the shareable URL.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2021-32584

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

In the Linux kernel before 5.15.3, fs/quota/quota_tree.c does not validate the block number in the quota tree (on disk). This can, for example, lead to a kernel/locking/rwsem.c use-after-free if there is a corrupted quota file.

What

In the Linux kernel before 5.15.3, fs/quota/quota_tree.c does not validate the block number in the quota tree (on disk). This can, for example, lead to a kernel/locking/rwsem.c use-after-free if there is a corrupted quota file.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

In the Linux kernel before 5.15.3, fs/quota/quota_tree.c does not validate the block number in the quota tree (on disk). This can, for example, lead to a kernel/locking/rwsem.c use-after-free if there is a corrupted quota file.

Why

The program can continue using memory after it has been released, producing unsafe and attacker-influenceable behaviour.

How

An attacker operating through local access may attempt exploitation without authentication after a user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
local access → Use After Free → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Local
Privileges required
None: unauthenticated exploitation is possible
User interaction
Required interaction required
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-416

CWE-416: Use After Free. The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UIRequiredUser interaction: Another user must perform an action for exploitation to succeed.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
Post-exploitation / living off the land
The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
UnauthenticatedCWE-416Public exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

BSI · German · WID-SEC-2022-0156Linux Kernel: Mehrere Schwachstellen

Ein lokaler Angreifer kann mehrere Schwachstellen im Linux Kernel ausnutzen, um seine Privilegien zu erweitern, einen Denial of Service Zustand auszulösen und mehrere nicht spezifizierte Angriffe durchzuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20220323Security Bulletin 23 Mar 2022

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 23 Mar 2022, published on 23 March 2022. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2023-AVI-0315Multiples vulnérabilités dans le noyau Linux d'Ubuntu

e.org/CVERecord?id=CVE-2021-28712 Référence CVE CVE-2021-28713 https://www.cve.org/CVERecord?id=CVE-2021-28713 Référence CVE CVE-2021-3428 https://www.cve.org/CVERecord?id=CVE-2021-3428 Référence CVE CVE-2021-3659 https://www.cve.org/CVERecord?id=CVE-2021-3659 Référence CVE CVE-2021-3669 https://www.cve.org/CVERecord?id=CVE-2021-3669 Référence CVE CVE-2021-3732 https://www.cve.org/CVERecord?id=CVE-2021-3732 Référence CVE CVE-2021-3772 https://www.cve.org/CVERecord?id=CVE-2021-3772 Référence CVE CVE-2021-4149 https://www.cve.org/CVERecord?id=CVE-2021-4149 Référence CVE CVE-2021-4203 https://www.cve.org/CVERecord?id=CVE-2021-4203 Référence CVE CVE-2021-45868 https://www.cve.org/CVERecord?id=CVE-2021-45868 Référence CVE CVE-2022-0487 https://www.cve.org/CVERecord?id=CVE-2022-0487 Référence CVE CVE-2022-0494 https://www.cve.org/CVERecord?id=CVE-2022-0494 Référence CVE CVE-2022-0617 https://www.cve.org/CVERecord?id=CVE-2022-0617 Référence CVE CVE-2022-1016 https://www.cve.org/CVERecord?id=CVE-2022-1016 Référence CVE CVE-2022-1195 https://www.cve.org/CVERecord?id=CVE-2022-1195 Référence CVE CVE-2022-1205 https://www.cve.org/CVERecord?id=CVE-2022-1205 Référence CVE CVE-2022-1462 https://www.cve.org/CVERecord?id=CVE-2022-1462 Référence CVE CVE-2022-1516 https://www.cve.org/CVERecord?id=CVE-2022-1516 R

Official advisory ↗
CERT-FR · French · CERTFR-2023-AVI-0148Multiples vulnérabilités dans le noyau Linux de SUSE

d?id=CVE-2020-16119 Référence CVE CVE-2020-24588 https://www.cve.org/CVERecord?id=CVE-2020-24588 Référence CVE CVE-2020-36557 https://www.cve.org/CVERecord?id=CVE-2020-36557 Référence CVE CVE-2020-36558 https://www.cve.org/CVERecord?id=CVE-2020-36558 Référence CVE CVE-2021-26341 https://www.cve.org/CVERecord?id=CVE-2021-26341 Référence CVE CVE-2021-33655 https://www.cve.org/CVERecord?id=CVE-2021-33655 Référence CVE CVE-2021-33656 https://www.cve.org/CVERecord?id=CVE-2021-33656 Référence CVE CVE-2021-34981 https://www.cve.org/CVERecord?id=CVE-2021-34981 Référence CVE CVE-2021-39713 https://www.cve.org/CVERecord?id=CVE-2021-39713 Référence CVE CVE-2021-45868 https://www.cve.org/CVERecord?id=CVE-2021-45868 Référence CVE CVE-2022-1011 https://www.cve.org/CVERecord?id=CVE-2022-1011 Référence CVE CVE-2022-1048 https://www.cve.org/CVERecord?id=CVE-2022-1048 Référence CVE CVE-2022-1353 https://www.cve.org/CVERecord?id=CVE-2022-1353 Référence CVE CVE-2022-1462 https://www.cve.org/CVERecord?id=CVE-2022-1462 Référence CVE CVE-2022-1652 https://www.cve.org/CVERecord?id=CVE-2022-1652 Référence CVE CVE-2022-1679 https://www.cve.org/CVERecord?id=CVE-2022-1679 Référence CVE CVE-2022-20132 https://www.cve.org/CVERecord?id=CVE-2022-20132 Référence CVE CVE-2022-20166 https://www.cve.org/CVERecord?id=CVE-2022-201

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-393Multiples vulnérabilités dans le noyau Linux de SUSE

su-20221329-1/ Bulletin de sécurité SUSE suse-su-20221335-1 du 25 avril 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20221335-1/ Bulletin de sécurité SUSE suse-su-20221369-1 du 25 avril 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20221369-1/ Bulletin de sécurité SUSE suse-su-20221402-1 du 26 avril 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20221402-1/ Bulletin de sécurité SUSE suse-su-20221407-1 du 26 avril 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20221407-1/ Référence CVE CVE-2021-39713 https://www.cve.org/CVERecord?id=CVE-2021-39713 Référence CVE CVE-2021-45868 https://www.cve.org/CVERecord?id=CVE-2021-45868 Référence CVE CVE-2022-0812 https://www.cve.org/CVERecord?id=CVE-2022-0812 Référence CVE CVE-2022-0850 https://www.cve.org/CVERecord?id=CVE-2022-0850 Référence CVE CVE-2022-0854 https://www.cve.org/CVERecord?id=CVE-2022-0854 Référence CVE CVE-2022-1011 https://www.cve.org/CVERecord?id=CVE-2022-1011 Référence CVE CVE-2022-1016 https://www.cve.org/CVERecord?id=CVE-2022-1016 Référence CVE CVE-2022-1048 https://www.cve.org/CVERecord?id=CVE-2022-1048 Référence CVE CVE-2022-1055 https://www.cve.org/CVERecord?id=CVE-2022-1055 Référence CVE CVE-2022-1195 https://www.cve.org/CVERecord?id=CVE-2022-1195 R

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-374Multiples vulnérabilités dans le noyau Linux de SUSE

De multiples vulnérabilités ont été découvertes dans le noyau Linux de SUSE. Certaines d'entre elles permettent à un attaquant de provoquer un problème de sécurité non spécifié par l'éditeur, un déni de service et une atteinte à la confidentialité des données.

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-362Multiples vulnérabilités dans le noyau Linux de SUSE

https://www.suse.com/support/update/announcement/2022/suse-su-20221268-1/ Bulletin de sécurité SUSE 20221269-1 du 19 avril 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20221269-1/ Bulletin de sécurité SUSE 20221270-1 du 20 avril 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20221270-1/ Référence CVE CVE-2021-0920 https://www.cve.org/CVERecord?id=CVE-2021-0920 Référence CVE CVE-2021-39698 https://www.cve.org/CVERecord?id=CVE-2021-39698 Référence CVE CVE-2021-39713 https://www.cve.org/CVERecord?id=CVE-2021-39713 Référence CVE CVE-2021-44879 https://www.cve.org/CVERecord?id=CVE-2021-44879 Référence CVE CVE-2021-45868 https://www.cve.org/CVERecord?id=CVE-2021-45868 Référence CVE CVE-2022-0487 https://www.cve.org/CVERecord?id=CVE-2022-0487 Référence CVE CVE-2022-0492 https://www.cve.org/CVERecord?id=CVE-2022-0492 Référence CVE CVE-2022-0516 https://www.cve.org/CVERecord?id=CVE-2022-0516 Référence CVE CVE-2022-0617 https://www.cve.org/CVERecord?id=CVE-2022-0617 Référence CVE CVE-2022-0644 https://www.cve.org/CVERecord?id=CVE-2022-0644 Référence CVE CVE-2022-0812 https://www.cve.org/CVERecord?id=CVE-2022-0812 Référence CVE CVE-2022-0850 https://www.cve.org/CVERecord?id=CVE-2022-0850 Référence CVE CVE-2022-0854 https://www.cve.org/CVERecord?id=CVE-2022-0854 R

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-353Multiples vulnérabilités dans le noyau Linux de SUSE

u-20221230-1/ Bulletin de sécurité SUSE su-20221242-1 du 15 avril 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20221242-1/ Bulletin de sécurité SUSE su-20221246-1 du 15 avril 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20221246-1/ Bulletin de sécurité SUSE su-20221248-1 du 15 avril 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20221248-1/ Référence CVE CVE-2021-0920 https://www.cve.org/CVERecord?id=CVE-2021-0920 Référence CVE CVE-2021-39698 https://www.cve.org/CVERecord?id=CVE-2021-39698 Référence CVE CVE-2021-39713 https://www.cve.org/CVERecord?id=CVE-2021-39713 Référence CVE CVE-2021-45868 https://www.cve.org/CVERecord?id=CVE-2021-45868 Référence CVE CVE-2022-0001 https://www.cve.org/CVERecord?id=CVE-2022-0001 Référence CVE CVE-2022-0002 https://www.cve.org/CVERecord?id=CVE-2022-0002 Référence CVE CVE-2022-0812 https://www.cve.org/CVERecord?id=CVE-2022-0812 Référence CVE CVE-2022-0850 https://www.cve.org/CVERecord?id=CVE-2022-0850 Référence CVE CVE-2022-0854 https://www.cve.org/CVERecord?id=CVE-2022-0854 Référence CVE CVE-2022-1016 https://www.cve.org/CVERecord?id=CVE-2022-1016 Référence CVE CVE-2022-1048 https://www.cve.org/CVERecord?id=CVE-2022-1048 Référence CVE CVE-2022-1055 https://www.cve.org/CVERecord?id=CVE-2022-1055 R

Official advisory ↗
CERT-FR · French · CERTFR-2022-AVI-341Multiples vulnérabilités dans le noyau Linux de SUSE

https://www.suse.com/support/update/announcement/2022/suse-su-20221182-1/ Bulletin de sécurité SUSE suse-su-20221183-1 du 13 avril 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20221183-1/ Bulletin de sécurité SUSE suse-su-20221189-1 du 13 avril 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20221189-1/ Bulletin de sécurité SUSE suse-su-20221192-1 du 13 avril 2022 https://www.suse.com/support/update/announcement/2022/suse-su-20221192-1/ Référence CVE CVE-2021-39698 https://www.cve.org/CVERecord?id=CVE-2021-39698 Référence CVE CVE-2021-45402 https://www.cve.org/CVERecord?id=CVE-2021-45402 Référence CVE CVE-2021-45868 https://www.cve.org/CVERecord?id=CVE-2021-45868 Référence CVE CVE-2022-0850 https://www.cve.org/CVERecord?id=CVE-2022-0850 Référence CVE CVE-2022-0854 https://www.cve.org/CVERecord?id=CVE-2022-0854 Référence CVE CVE-2022-1011 https://www.cve.org/CVERecord?id=CVE-2022-1011 Référence CVE CVE-2022-1016 https://www.cve.org/CVERecord?id=CVE-2022-1016 Référence CVE CVE-2022-1048 https://www.cve.org/CVERecord?id=CVE-2022-1048 Référence CVE CVE-2022-1055 https://www.cve.org/CVERecord?id=CVE-2022-1055 Référence CVE CVE-2022-1195 https://www.cve.org/CVERecord?id=CVE-2022-1195 Référence CVE CVE-2022-1198 https://www.cve.org/CVERecord?id=CVE-2022-1198 R

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-019346Linux Kernel における解放済みメモリの使用に関する脆弱性

Linux Kernel には、解放済みメモリの使用に関する脆弱性が存在します。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
n/a: n/a
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 18 Mar 2022 · Last source change 4 Aug 2024, 04:54 UTC · CWE-416 · Use After Free

CVE recordCVE.org · 5.1
CVSS sourceNIST NVD
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2021-32584
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceNIST NVD
NVD statusNVD modified after enrichment

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2021-45868 · cve.blacktree.nl