Linux Kernel up to 5.15.2 Quota Tree fs/quota/quota_tree.c use after free

CVSS Meta Temp Score
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CTI Interest Score
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5.0$0-$5k0.00

Summaryinfo

A vulnerability, which was classified as critical, has been found in Linux Kernel up to 5.15.2. Affected by this issue is some unknown functionality of the file fs/quota/quota_tree.c of the component Quota Tree Handler. This manipulation causes use after free. This vulnerability is tracked as CVE-2021-45868. Moreover, an exploit is present. It is advisable to upgrade the affected component.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 5.15.2 (Operating System). Affected by this vulnerability is an unknown functionality of the file fs/quota/quota_tree.c of the component Quota Tree Handler. The manipulation with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability.

The weakness was disclosed 03/18/2022 as Bug 214655. It is possible to read the advisory at bugzilla.kernel.org. This vulnerability is known as CVE-2021-45868 since 12/27/2021. Technical details and also a public exploit are known.

It is possible to download the exploit at bugzilla.kernel.org. It is declared as proof-of-concept. We expect the 0-day to have been worth approximately $5k-$25k. The vulnerability scanner Nessus provides a plugin with the ID 276356 (TencentOS Server 3: kernel (TSSA-2023:0340)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 5.15.3 eliminates this vulnerability. The upgrade is hosted for download at cdn.kernel.org. Applying a patch is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at Tenable (276356). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Productinfo

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Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.0

VulDB Base Score: 5.5
VulDB Temp Score: 5.0
VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Partially

Availability: 🔍
Access: Public
Status: Proof-of-Concept
Download: 🔍

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 276356
Nessus Name: TencentOS Server 3: kernel (TSSA-2023:0340)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔍

Upgrade: Kernel 5.15.3
Patch: git.kernel.org

Timelineinfo

12/27/2021 🔍
03/18/2022 +81 days 🔍
03/18/2022 +0 days 🔍
11/23/2025 +1346 days 🔍

Sourcesinfo

Vendor: kernel.org

Advisory: Bug 214655
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2021-45868 (🔍)
GCVE (CVE): GCVE-0-2021-45868
GCVE (VulDB): GCVE-100-195427
scip Labs: https://www.scip.ch/en/?labs.20161013

Entryinfo

Created: 03/18/2022 11:30
Updated: 11/23/2025 12:06
Changes: 03/18/2022 11:30 (48), 11/23/2025 12:06 (16)
Complete: 🔍
Cache ID: 216::103

Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

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