SSRF in Apache Activemq

CVE-2021-21342

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.

Vulnerability class: Insecure Deserialization

EPSS: 0.500 (98.8th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-21342?
CVE-2021-21342 is a medium-severity vulnerability in Apache Activemq, classified under Deserialization of Untrusted Data. CVSS score: 5.3/10. Published 2021-03-23.
How severe is CVE-2021-21342?
Medium severity. CVSS v3 base score is 5.3 out of 10.
Is CVE-2021-21342 known to be exploited?
4 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.