HOMEVULNERABILITIESCVE-2021-45868
MEDIUM

CVE-2021-45868

CWE-416Published: March 18, 2022· Updated: Jun 17, 2026

5.5
CVSS v3.1

Official Description

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.

NVD Source

Technical Analysis

CVE-2021-45868 requires local access, meaning attackers must already have a foothold on the target system.

Exploitation does not require any privileges, though user interaction (Required) is needed, which slightly reduces the risk of mass automated attacks.

A successful exploit results in availability disruption (denial of service), with a CVSS base score of 5.5.

From a weakness classification perspective (CWE-416): Use-after-free vulnerabilities involve accessing memory after it has been freed, often enabling arbitrary code execution.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorLocal
Attack ComplexityLow
Privileges Req.None
User InteractionRequired
ScopeUnchanged
Impact
ConfidentialityNone
IntegrityNone
AvailabilityHigh
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Affected Vendors & Products

Linux1 product(s)
linux kernel
netapp16 product(s)
h300s firmwareh300sh700s firmwareh700sh300e firmwareh300eh500e firmwareh500eh700e firmwareh700eh410s firmwareh410s+4
Source: NVD CPE · 17 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

PATCHhttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9bf3d20331295b1ecb81f4ed9ef358c51699a050
PATCHhttps://www.openwall.com/lists/oss-security/2022/03/17/1
PATCHhttps://www.openwall.com/lists/oss-security/2022/03/17/2
PATCHhttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9bf3d20331295b1ecb81f4ed9ef358c51699a050
PATCHhttps://www.openwall.com/lists/oss-security/2022/03/17/1
PATCHhttps://www.openwall.com/lists/oss-security/2022/03/17/2
ADVISORYhttps://bugzilla.kernel.org/show_bug.cgi?id=214655
ADVISORYhttps://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.3
ADVISORYhttps://security.netapp.com/advisory/ntap-20220419-0003/
ADVISORYhttps://bugzilla.kernel.org/show_bug.cgi?id=214655
ADVISORYhttps://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.3
ADVISORYhttps://security.netapp.com/advisory/ntap-20220419-0003/

All References (12)

→
https://bugzilla.kernel.org/show_bug.cgi?id=214655Exploit · Issue Tracking · Vendor Advisory
→
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.3Mailing List · Release Notes · Vendor Advisory
→
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9bf3d20331295b1ecb81f4ed9ef358c51699a050Mailing List · Patch · Vendor Advisory
→
https://security.netapp.com/advisory/ntap-20220419-0003/Third Party Advisory
→
https://www.openwall.com/lists/oss-security/2022/03/17/1Exploit · Mailing List · Patch · Third Party Advisory
→
https://www.openwall.com/lists/oss-security/2022/03/17/2Exploit · Mailing List · Patch · Third Party Advisory
→
https://bugzilla.kernel.org/show_bug.cgi?id=214655Exploit · Issue Tracking · Vendor Advisory
→
https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.3Mailing List · Release Notes · Vendor Advisory
→
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9bf3d20331295b1ecb81f4ed9ef358c51699a050Mailing List · Patch · Vendor Advisory
→
https://security.netapp.com/advisory/ntap-20220419-0003/Third Party Advisory
→
https://www.openwall.com/lists/oss-security/2022/03/17/1Exploit · Mailing List · Patch · Third Party Advisory
→
https://www.openwall.com/lists/oss-security/2022/03/17/2Exploit · Mailing List · Patch · Third Party Advisory

Quick Facts

CVE IDCVE-2021-45868
CVSS Score5.5 / 10
SeverityMEDIUM
WeaknessCWE-416
CISA KEVNo
Affected2 vendor(s)
PublishedMar 18, 2022

Related CVEs (CWE-416)

CVE-2012-1973
10.0
CVE-2012-1972
10.0
CVE-2024-43102
10.0
CVE-2026-13782
10.0
CVE-2011-0982
10.0
CVE-2012-1974
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2021-45868 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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