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 a server-side forgery request. 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.
History

Wed, 07 Oct 2026 19:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 23 May 2025 18:00:00 +0000

Type Values Removed Values Added
First Time appeared Apache
Apache activemq
Apache jmeter
Netapp
Netapp oncommand Insight
Xstream
Xstream xstream
CPEs cpe:2.3:a:xstream_project:xstream:*:*:*:*:*:*:*:* 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:netapp:oncommand_insight:-:*:*:*:*:*:*:*
cpe:2.3:a:xstream:xstream:*:*:*:*:*:*:*:*
Vendors & Products Xstream Project
Xstream Project xstream
Apache
Apache activemq
Apache jmeter
Netapp
Netapp oncommand Insight
Xstream
Xstream xstream

cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published: 2021-03-22T23:40:39.000Z

Updated: 2026-10-07T18:47:34.161Z

Reserved: 2020-12-22T00:00:00.000Z

Link: CVE-2021-21342

cve-icon Vulnrichment

Updated: 2024-08-03T18:09:15.862Z

cve-icon NVD

Status : Analyzed

Published: 2021-03-23T00:15:12.490

Modified: 2026-10-07T19:17:20.313

Link: CVE-2021-21342

cve-icon Redhat

Severity : Moderate

Publid Date: 2021-03-12T00:00:00Z

Links: CVE-2021-21342 - Bugzilla