CVE-2021-21346 XStream is vulnerable to an Arbitrary Code Execution attack

What is CVE-2021-21346?

CVE-2021-21346 is a medium-severity unsafe deserialization vulnerability in Apache Activemq, published on 22 Mar 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.

Official 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.

Weakness: CWE-502, CWE-434

Which versions are affected by CVE-2021-21346?

3 open source packages ship an affected version, including activemq and com.thoughtworks.xstream:xstream. It affects 16 products.

Products include Apache Activemq, Apache Jmeter, Debian Debian Linux, Fedoraproject Fedora, Netapp Oncommand Insight, Oracle Banking Enterprise Default Management and 10 more.

How do I fix CVE-2021-21346?

Upgrade activemq to 5.15.14 or later.

Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.

Is CVE-2021-21346 being exploited?

There is no known exploitation of CVE-2021-21346 in the wild and no public exploit code.

Other vulnerabilities in Apache Activemq

• CVE-2023-46604 Apache ActiveMQ Deserialization of Untrusted Data Exploited Critical 10.0
• CVE-2016-3088 Apache ActiveMQ Improper Input Validation Exploited Critical 9.8
• CVE-2026-34197 Apache ActiveMQ Improper Input Validation Exploited High 8.8
• CVE-2020-11998 Remote code execution in Apache ActiveMQ Critical 9.8
• CVE-2013-7285 Command Injection in Xstream Critical 9.8

All Apache Activemq vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as BIT-activemq-2021-21346, DEBIAN-CVE-2021-21346, GHSA-4hrm-m67v-5cxr, UBUNTU-CVE-2021-21346.