CVE-2021-45868

MEDIUMNVD 5.55.5—

5.5

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.

CVSS v3: 5.5
EG Score: 5.5(medium)
EPSS: 44.5%
KEV: Not listed

Published

March 18, 2022

Last Modified

November 21, 2024

References (12)

cve@mitrehttps://bugzilla.kernel.org/show_bug.cgi?id=214655
cve@mitrehttps://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.3
cve@mitrehttps://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9bf3d20331295b1ecb81f4ed9ef358c51699a050
cve@mitrehttps://security.netapp.com/advisory/ntap-20220419-0003/
cve@mitrehttps://www.openwall.com/lists/oss-security/2022/03/17/1
cve@mitrehttps://www.openwall.com/lists/oss-security/2022/03/17/2
af854a3a-2127-422b-91ae-364da2661108https://bugzilla.kernel.org/show_bug.cgi?id=214655
af854a3a-2127-422b-91ae-364da2661108https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.15.3
af854a3a-2127-422b-91ae-364da2661108https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=9bf3d20331295b1ecb81f4ed9ef358c51699a050
af854a3a-2127-422b-91ae-364da2661108https://security.netapp.com/advisory/ntap-20220419-0003/
af854a3a-2127-422b-91ae-364da2661108https://www.openwall.com/lists/oss-security/2022/03/17/1
af854a3a-2127-422b-91ae-364da2661108https://www.openwall.com/lists/oss-security/2022/03/17/2

Patch Availability(3)

Vendor / Ecosystem	Fixed in / Patch	Released	Source
ubuntu	linux-tools-4.4.0-1155-aws (4.4.0-1155.170) @ xenial	2026-05-26	ubuntu
ubuntu	linux-tools-4.4.0-239-lowlatency (4.4.0-239.273) @ xenial	2026-05-26	ubuntu
ubuntu	linux-image-4.4.0-1117-aws (4.4.0-1117.123) @ trusty	2026-05-26	ubuntu

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-416Use After Free

All Vendor Advisories

(4)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 11× in last 7d / 20× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

2026-06-08 14:15 UTCEPSS rescore
2026-06-08 14:15 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-07 15:23 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-06 13:46 UTCEPSS rescore
2026-06-05 22:45 UTCEPSS rescore
2026-06-05 06:09 UTCEPSS rescore
2026-06-05 06:09 UTCEPSS rescore
2026-06-04 13:10 UTCEPSS rescore
2026-06-04 13:10 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-02 20:11 UTCEPSS rescore
2026-06-01 13:50 UTCEPSS rescore
2026-06-01 13:50 UTCEPSS rescore
2026-05-31 22:29 UTCEPSS rescore
2026-05-31 22:29 UTCEPSS rescore
2026-05-31 00:15 UTCEPSS rescore
2026-05-31 00:15 UTCEPSS rescore
2026-05-29 13:42 UTCEPSS rescore

Frequently asked(5)

What is CVE-2021-45868?

CVE-2021-45868 is a medium vulnerability published on March 18, 2022. 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.

When was CVE-2021-45868 disclosed?

CVE-2021-45868 was first published in the National Vulnerability Database on March 18, 2022, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-45868 actively exploited?

CVE-2021-45868 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 44.5% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-45868?

CVE-2021-45868 has a CVSS v3 base score of 5.5 (NVD).

How do I remediate CVE-2021-45868?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-45868, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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CVE-2021-45868

Published

Last Modified

References (12)

Patch Availability(3)

Weakness Classification(1)

All Vendor Advisories

Data Freshness Timeline

Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-45868?

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CVE-2021-45868

📅 Published

🔄 Last Modified

🔗 References (12)

Patch Availability(3)

Weakness Classification(1)

All Vendor Advisories

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-45868?

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References (12)

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