CVE-2021-39144

XStream is vulnerable to a Remote Command Execution attack

HIGH
8.5
CVSS Score
Published: August 23, 2021 at 12:00 AM UTC
Updated: June 17, 2026 at 04:03 AM UTC
15 products affected across 5 vendorsDebian LinuxFedoraSnapmanager

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Severity
HIGH8.5
Exploitation
CISA KEV
Exploit prediction
EPSS 98%
SSVC
Active

Actively Exploited

CISA Known Exploited Vulnerabilities (KEV) Catalog

EPSS Score98.1%

EPSS (Exploit Prediction Scoring System) estimates a 98.1% chance this CVE is exploited in the wild within the next 30 days — higher than 100% of all CVEs. It complements CVSS: a high EPSS on a mid-severity CVE can still be urgent.

XStream contains a remote code execution vulnerability that allows an attacker to manipulate the processed input stream and replace or inject objects that result in the execution of a local command on the server. This vulnerability can affect multiple products, including but not limited to VMware Cloud Foundation.

Required Action
Apply updates per vendor instructions.
Ransomware Use
Unknown
Added to KEV
Mar 10, 2023
Remediation Due
Mar 31, 2023
1311 days overdue

Description

XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker has sufficient rights to execute commands of the 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. XStream 1.4.18 uses no longer a blacklist by default, since it cannot be secured for general purpose.

SSVC — Action Prioritization

SSVCActiveNot automatableTotal impact

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

CVSS

8.5HIGHGitHub_M
Attack Vector
NETWORK
Complexity
HIGH
Privileges
LOW
User Interaction
NONE
Scope
CHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Vector?

Quick Info

StatusANALYZED
CWE
CWE-94CWE-502CWE-306

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