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Fencer Vulns
medium 5.3

CVE-2021-21350 json

XStream is vulnerable to an Arbitrary Code Execution attack

published 2021-03-22 5 y ago modified 2026-10-07 32 d ago also BIT-activemq-2021-21350 , EUVD-2021-0595 , GHSA-43gc-mjxg-gvrq

cvss
5.3
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
15.2%
EPSS 15.2% chance of exploitation in 30 days, percentile 96%
public exploits
0
none known

Summary

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 execute arbitrary code 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.

Patch / fix

  • maven com.thoughtworks.xstream:xstream 1.4.16
  • bitnami activemq 5.15.14
  • apache activemq 5.15.14
  • apache jmeter 5.5
  • xstream xstream 1.4.16
  • libxstream-java Debian 14, Debian 13, Debian 12 1.4.15-2

debian advisories DEBIAN-CVE-2021-21350

  • libxstream-java Ubuntu 18.04 LTS 1.4.11.1-1~18.04.2
  • libxstream-java Ubuntu 20.04 LTS 1.4.11.1-1ubuntu0.2
  • libxstream-java Ubuntu Pro 14.04 LTS 1.4.7-1ubuntu0.1+esm2
  • libxstream-java Ubuntu Pro 16.04 LTS 1.4.8-1ubuntu0.1+esm3

ubuntu advisories UBUNTU-CVE-2021-21350

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • xstream RHEL 7 1.3.1-13.el7_9
  • xstream-javadoc RHEL 7 1.3.1-13.el7_9

red hat advisories RHSA-2021:1354

  • xstream SLE Module for Development Tools 15 SP3, SLE Module for Development Tools 15 SP2, Manager Server Module 4.2 +1 more 1.4.16-3.8.1

suse advisories SUSE-SU-2021:1840-2SUSE-SU-2021:1840-1

  • xstream openSUSE Tumbleweed 1.4.18-1.1
  • xstream openSUSE Leap 15.3 1.4.16-3.8.1
  • xstream openSUSE Leap 15.2 1.4.16-lp152.2.6.1

opensuse advisories openSUSE-SU-2024:10592-1openSUSE-SU-2021:1840-1openSUSE-SU-2021:0832-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2021-21350 updated cvss 8.1

XStream: Unsafe deserizaliation of com.sun.org.apache.bcel.internal.util.ClassLoader

  • Red Hat BPM Suite 6 xstream
    affected: no fix planned “Out of support scope”
  • Red Hat Integration Camel K 1 xstream
    affected: no fix available
  • Red Hat JBoss A-MQ 6 xstream Red Hat JBoss BRMS 5 xstream Red Hat JBoss BRMS 6 xstream Red Hat JBoss Data Grid 7 xstream Red Hat JBoss Data Virtualization 6 xstream Red Hat JBoss Fuse 6 xstream
    +2 more products
    Red Hat JBoss Fuse Service Works 6 xstream Red Hat JBoss SOA Platform 5 xstream
    affected: no fix planned “Out of support scope”
  • Red Hat Data Grid 8.2.0
    fixed: vendor fix RHSA-2021:2139
  • Red Hat Enterprise Linux Client Optional (v. 7) xstream 1.3.1-13.el7_9, xstream-javadoc 1.3.1-13.el7_9 Red Hat Enterprise Linux ComputeNode Optional (v. 7) xstream 1.3.1-13.el7_9, xstream-javadoc 1.3.1-13.el7_9 Red Hat Enterprise Linux Server Optional (v. 7) xstream 1.3.1-13.el7_9, xstream-javadoc 1.3.1-13.el7_9 Red Hat Enterprise Linux Workstation Optional (v. 7) xstream 1.3.1-13.el7_9, xstream-javadoc 1.3.1-13.el7_9
    fixed: vendor fix RHSA-2021:1354
  • Red Hat Fuse 7.10
    fixed: vendor fix RHSA-2021:5134
  • Red Hat Integration
    fixed: vendor fix RHSA-2021:4918
  • Red Hat Integration Camel Quarkus 2
    fixed: vendor fix RHSA-2021:4767
show 3 more
  • Red Hat RHDM 7.11.0
    fixed: vendor fix RHSA-2021:2476
  • Red Hat RHPAM 7.11.0
    fixed: vendor fix RHSA-2021:2475
  • Red Hat Integration Camel Quarkus 1 xstream Red Hat OpenShift Container Platform 3.11 jenkins Red Hat OpenShift Container Platform 4 jenkins
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
32 d ago

Exploit prediction

15.23% chance of exploitation in the next 30 days, higher than 96% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • x-stream.github.io https://x-stream.github.io/CVE-2021-21350.html referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
GitHub 3.1 5.3 CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N
NVD 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 7.5 AV:N/AC:L/Au:N/C:P/I:P/A:P
OSV 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected packages

ecosystem package affected fixed in
maven com.thoughtworks.xstream:xstream
<1.4.16
1.4.16
bitnami activemq
<5.15.14
>=5.16.0, <=5.16.0
>=5.16.1, <=5.16.1
5.15.14

Affected products

  • x-stream xstream

Classification

Weakness
  • CWE-434 Unrestricted Upload of File with Dangerous Type
  • CWE-502 Deserialization of Untrusted Data

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.