What is the CVSS score of CVE-2021-20291?

CVE-2021-20291 has a CVSS 3.1 base score of 6.5 (Medium). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H. EPSS exploitation probability: 1.6%.

Is there a public PoC exploit available for CVE-2021-20291?

Yes, a public proof-of-concept exploit is available for CVE-2021-20291. Prioritise patching immediately. EPSS: 1.6%.

Is there a patch available for CVE-2021-20291?

Yes, a patch is available for CVE-2021-20291. Update the affected software to the latest version immediately.

Storage CVE-2021-20291

MEDIUM

Improper Locking (CWE-667)

2021-04-01 secalert@redhat.com

Denial Of Service Red Hat Enterprise Linux Fedora Openshift Container Platform Storage Fedoraproject

6.5

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-667 ASVS 5.0 V15 - Secure Coding and Architecture Proper locking
Impact	CVSS score of 6.5 (MEDIUM). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the medium-severity affected system.

This Month Plan within 30 days. Why: MEDIUM severity (CVSS 4.0-6.9).

Patch available 1.6% exploitation probability (EPSS)

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AnalysisAI

A deadlock vulnerability was found in 'github.com/containers/storage' in versions before 1.28.1. Rated medium severity (CVSS 6.5), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affected Packages

go github.com/containers/storage fix: 1.28.1

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in go

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-667. A deadlock vulnerability was found in 'github.com/containers/storage' in versions before 1.28.1. When a container image is processed, each layer is unpacked using tar. If one of those layers is not a valid tar archive this causes an error leading to an unexpected situation where the code indefinitely waits for the tar unpacked stream, which never finishes. An attacker could use this vulnerability to craft a malicious image, which when downloaded and stored by an application using containers/storage, would then cause a deadlock leading to a Denial of Service (DoS). Affected products include: Storage Project Storage, Redhat Openshift Container Platform, Redhat Enterprise Linux, Fedoraproject Fedora. Version information: before 1.28.1..

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 6.5 MEDIUM

AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

DescriptionNVD

A deadlock vulnerability was found in 'github.com/containers/storage' in versions before 1.28.1. When a container image is processed, each layer is unpacked using tar. If one of those layers is not a valid tar archive this causes an error leading to an unexpected situation where the code indefinitely waits for the tar unpacked stream, which never finishes. An attacker could use this vulnerability to craft a malicious image, which when downloaded and stored by an application using containers/storage, would then cause a deadlock leading to a Denial of Service (DoS).

Threat Intelligence Overview

EPSS Score

1.6%

Top 27% exploitable

Exploit

POC

Public exploit code exists

Data Quality

2 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity MEDIUM

CISA KEV No

Public POC Yes

EPSS 1.6%

Patch available Yes

Active threat No

Deciding rule

MEDIUM severity (CVSS 4.0-6.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +2

CVSS: +32

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Denial of Service MEDIUM

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.

Affected Products (CPE)NVD

cpe:2.3:a:storage_project:storage:*:*:*:*:*:*:*:*

cpe:2.3:a:redhat:openshift_container_platform:4.0:*:*:*:*:*:*:*

cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*

cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*

cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

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References

Advisories & patches

PATCH https://bugzilla.redhat.com/show_bug.cgi?id=1939485 REF https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/R5D7XL7FL24TWFMGQ3K2S72EOUSLZMKL/ REF https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPYOHNG2Q7DCAQZMGYLMENLKALGDLG3X/ REF https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/WX24EITRXVHDM5M223BVTJA2ODF2FSHI/ REF https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNMB7O2UIXE34PGSCSOULGHPX5LIJBMM/

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