CVE-2021-39144 HIGH

CVE-2021-39144: XStream is vulnerable to a Remote Command Execution attack

Vendor X-Stream
Product xstream
Weakness CWE-94 · Code injection
KEV Status Known Exploited
Published August 23, 2021
Last update October 21, 2025

CVSS base score

8.5/10
Attack vector Network
Attack complexity High
Privileges required Low
User interaction None
Confidentiality High
Integrity High

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

What the vulnerability does

01Description

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.

CISA mandated remediation

02CISA Required Action

Apply updates per vendor instructions.

Key dates

03Disclosure timeline

August 23, 2021 CVE published
October 21, 2025 Record updated