What is the CVSS score of CVE-2021-21343?

CVE-2021-21343 has a CVSS 3.1 base score of 7.5 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N. EPSS exploitation probability: 46.7%.

Is there a public PoC exploit available for CVE-2021-21343?

Yes, a public proof-of-concept exploit is available for CVE-2021-21343. Prioritise patching immediately. EPSS: 46.7%.

Is there a patch available for CVE-2021-21343?

Yes, a patch is available for CVE-2021-21343. Update the affected software to the latest version immediately.

Xstream CVE-2021-21343

HIGH

External Control of File Name or Path (CWE-73)

2021-03-23 security-advisories@github.com

Apache Java Code Injection Debian Oracle Activemq Debian Linux Fedora Oncommand Insight Retail Xstore Point Of Service Banking Platform Webcenter Portal Banking Virtual Account Management Communications Policy Management Communications Unified Inventory Management Xstream Jmeter Business Activity Monitoring Communications Billing And Revenue Management Elastic Charging Engine Banking Enterprise Default Management Netapp Fedoraproject

7.5

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-73 OWASP Top 10:2025 A06:2025 - Insecure Design ASVS 5.0 V5 - File Handling File name/path control
Impact	CVSS score of 7.5 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not 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 high-severity affected system.

Act Now Prioritize within 24-48h. Why: HIGH severity + EPSS > 10%.

Patch available 46.7% exploitation probability (EPSS)

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AnalysisAI

XStream is a Java library to serialize objects to XML and back again. Rated high severity (CVSS 7.5), 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

maven com.thoughtworks.xstream:xstream fix: 1.4.16

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in maven

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-73. XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability where the processed stream at unmarshalling time contains type information to recreate the formerly written objects. XStream creates therefore new instances based on these type information. An attacker can manipulate the processed input stream and replace or inject objects, that result in the deletion of a file on the local host. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.16. Affected products include: Netapp Oncommand Insight, Apache Activemq, Apache Jmeter, Xstream, Debian Debian Linux. Version information: version 1.4.16.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 7.5 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

High

Availability

None

DescriptionNVD

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability where the processed stream at unmarshalling time contains type information to recreate the formerly written objects. XStream creates therefore new instances based on these type information. An attacker can manipulate the processed input stream and replace or inject objects, that result in the deletion of a file on the local host. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.16.

Blast Radius

ecosystem impact

† from your stack dependencies † transitive graph · vuln.today resolves 4-path depth

1,338 maven packages depend on com.thoughtworks.xstream:xstream (145 direct, 1,195 indirect)

Ecosystem-wide dependent count for version 1.4.16.

Threat Intelligence Overview

Threat Score

4.4/10

Composite threat intelligence

EPSS Score

46.7%

Top 1% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

GitHub

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 HIGH

CISA KEV No

Public POC Yes

EPSS 46.7%

Patch available Yes

Active threat Yes

Deciding rule

HIGH severity + EPSS > 10%

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

Yes

Human Impact· derived

Medium

Priority Score

105

Low Medium High Critical

KEV: 0

EPSS: +47

CVSS: +38

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Code Injection CRITICAL

Code injection occurs when an application accepts user input and passes it directly into a language interpreter or evaluator without proper sanitization.

Affected Products (CPE)NVD

cpe:2.3:a:netapp:oncommand_insight:-:*:*:*:*:*:*:*

cpe:2.3:a:apache:activemq:*:*:*:*:*:*:*:*

cpe:2.3:a:apache:activemq:5.16.0:*:*:*:*:*:*:*

cpe:2.3:a:apache:activemq:5.16.1:*:*:*:*:*:*:*

cpe:2.3:a:apache:jmeter:*:*:*:*:*:*:*:*

cpe:2.3:a:xstream:xstream:*:*:*:*:*:*:*:*

cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*

cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

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

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

cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*

cpe:2.3:a:oracle:banking_enterprise_default_management:2.10.0:*:*:*:*:*:*:*

cpe:2.3:a:oracle:banking_enterprise_default_management:2.12.0:*:*:*:*:*:*:*

cpe:2.3:a:oracle:banking_platform:2.4.0:*:*:*:*:*:*:*

cpe:2.3:a:oracle:banking_platform:2.7.1:*:*:*:*:*:*:*

cpe:2.3:a:oracle:banking_platform:2.9.0:*:*:*:*:*:*:*

cpe:2.3:a:oracle:banking_platform:2.12.0:*:*:*:*:*:*:*

cpe:2.3:a:oracle:banking_virtual_account_management:14.2.0:*:*:*:*:*:*:*

cpe:2.3:a:oracle:banking_virtual_account_management:14.3.0:*:*:*:*:*:*:*

+ 18 more

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XStream is a Java library to serialize objects to XML and back again. Rated high severity (CVSS 7.7), this vulnerability

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CVE-2021-21341 HIGH Act Now POC

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XStream is a Java library to serialize objects to XML and back again. Rated high severity (CVSS 7.5), this vulnerability

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XStream is a Java library to serialize objects to XML and back again. Rated critical severity (CVSS 9.1), this vulnerabi

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XStream is a Java library to serialize objects to XML and back again. Rated high severity (CVSS 8.6), this vulnerability

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Same weakness CWE-73 – External Control of File Name or Path

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References

Advisories & patches

PATCH https://www.oracle.com/security-alerts/cpujan2022.html REF http://x-stream.github.io/changes.html#1.4.16 REF https://github.com/x-stream/xstream/security/advisories/GHSA-74cv-f58x-f9wf REF https://lists.apache.org/thread.html/r8244fd0831db894d5e89911ded9c72196d395a90ae655414d23ed0dd%40%3Cusers.activemq.apache.org%3E REF https://lists.apache.org/thread.html/r9ac71b047767205aa22e3a08cb33f3e0586de6b2fac48b425c6e16b0%40%3Cdev.jmeter.apache.org%3E REF https://lists.debian.org/debian-lts-announce/2021/04/msg00002.html REF https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP/ REF https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7/ REF https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB/ REF https://security.netapp.com/advisory/ntap-20210430-0002/ REF https://www.debian.org/security/2021/dsa-5004 REF https://www.oracle.com//security-alerts/cpujul2021.html REF https://www.oracle.com/security-alerts/cpuoct2021.html REF https://x-stream.github.io/security.html#workaround

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