CVE-2021-21344

XStream is vulnerable to an Arbitrary Code Execution attack

CRITICAL
9.8
CVSS Score
Published: March 22, 2021 at 11:40 PM UTC
Updated: October 7, 2026 at 07:17 PM UTC
16 products affected across 6 vendorsDebian LinuxFedoraMySQL Server

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Severity
CRITICAL9.8
Exploit prediction
EPSS 76%
SSVC
No known exploit

Description

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability which may allow a remote attacker to load and execute arbitrary code from a remote host only by manipulating the processed input stream. 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

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

References (15)

SSVC — Action Prioritization

SSVCNo known exploitAutomatableTotal impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-434CWE-502NVD-CWE-noinfo

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