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CVE-2021-43859

Denial of Service by injecting highly recursive collections or maps in XStream

Published: Feb 1, 2022Updated: Nov 3, 2025 Sources: CVE List NVD GHSA BDUCWE-400
NVD MITRE
7.5CVSSHIGH
EPSS Score
8.2%
Top 5.9%
CISA KEV
Not in KEV
Exploits
2 Known
Remediation
Patch Available
Am I actually vulnerable?1 Nuclei template available — see how to check your systems. How to verify

Description

XStream is an open source java library to serialize objects to XML and back again. Versions prior to 1.4.19 may allow a remote attacker to allocate 100% CPU time on the target system depending on CPU type or parallel execution of such a payload resulting in a denial of service only by manipulating the processed input stream. XStream 1.4.19 monitors and accumulates the time it takes to add elements to collections and throws an exception if a set threshold is exceeded. Users are advised to upgrade as soon as possible. Users unable to upgrade may set the NO_REFERENCE mode to prevent recursion. See GHSA-rmr5-cpv2-vgjf for further details on a workaround if an upgrade is not possible.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-400

Affected Products

Debian GNU/LinuxСообщество свободного программного обеспечения
On-premOS
Operating Systems / linux-distro
OpenShift Container PlatformRed Hat Inc.
SaaSSaaS Service
Cloud & SaaS / container-orchestration
Jboss FuseRed Hat Inc.
On-premWeb App
DevTools & CI / build-test-tools
Red Hat Descision ManagerRed Hat Inc.
On-premOS
Operating Systems / linux-distro
CodeReady StudioRed Hat Inc.
On-prem
Operating Systems / linux-distro
сообщество свободного программного обеспеченияoss-projectOperating Systemsaka сообщество свободного программного обеспечения, fsf
red hat inc.commercialUSOperating Systemsaka red hat
and 22 more affected products View all →

Attack Graph

Products CVE Techniques Tactics

Click technique nodes to view MITRE ATT&CK details. Scroll to zoom, drag to pan.

Exploitability

2 exploit sources identified

Exploit details including PoC links, Metasploit modules, and scanner templates are available after registration.

View exploit details
Official Patch Available

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://github.com/x-stream/xstream/security/advisories/GHSA-rmr5-cpv2-vgjf
github.com
https://x-stream.github.io/CVE-2021-43859.html
x-stream.github.io
https://github.com/x-stream/xstream/commit/e8e88621ba1c85ac3b8620337dd672e0c0c3a846
github.com
and 22 more references View all →

Timeline

Published
Feb 1, 2022
Last Updated
Nov 3, 2025

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