CVE-2021-21346
CriticalXStream is vulnerable to an Arbitrary Code Execution attack
Published Mar 22, 2021 · Updated Oct 9, 2026 · Also known as BIT-activemq-2021-21346, DEBIAN-CVE-2021-21346, GHSA-4hrm-m67v-5cxr, UBUNTU-CVE-2021-21346
Key Facts
Patch immediately- CVE-2021-21346 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Activemq (Apache), Jmeter (Apache), Oncommand Insight (Netapp) and 18 more products.
- It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
- EPSS estimates a 76% probability of exploitation in the next 30 days.
- Fixed versions are available, including Activemq 5.15.14, Jmeter 5.5, com.thoughtworks.xstream:xstream 1.4.16.
- Brandefense priority: patch immediately, because it is very likely to be exploited soon.
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
76%
Higher than 99.5% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
None known
Get the full CVE-2021-21346 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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.
Affected Products
86 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| ActivemqApache | 5.16.0, 5.16.1 | 5.15.14 |
| JmeterApache | See advisory | 5.5 |
| Oncommand InsightNetapp | See advisory | n/a |
| Banking Enterprise Default ManagementOracle | 2.10.0, 2.12.0 | n/a |
| Banking PlatformOracle | 2.12.0, 2.4.0, 2.7.1, 2.9.0 | n/a |
Patched Releases
Activemq
5.15.14
Jmeter
5.5
com.thoughtworks.xstream:xstream
1.4.16
libxstream-java
1.4.11.1-1+deb9u2, 1.4.11.1-1~18.04.2, 1.4.11.1-1ubuntu0.2, 1.4.15-2, 1.4.7-1ubuntu0.1+esm2, 1.4.8-1ubuntu0.1+esm3
Xstream
0:1.3.1-13.el7_9, 1.3.1-13.amzn2, 1.3.1-13.el7_9, 1.4.16-3.8.1, 1.4.16-lp152.2.6.1, 1.4.18-1.1, 1.4.16
xstream-benchmark
1.4.16-3.8.1, 1.4.16-lp152.2.6.1, 1.4.18-1.1
xstream-javadoc
1.3.1-13.amzn2, 1.3.1-13.el7_9, 1.4.16-3.8.1, 1.4.16-lp152.2.6.1, 1.4.18-1.1
xstream-parent
1.4.16-3.8.1, 1.4.16-lp152.2.6.1, 1.4.18-1.1
Timeline
Publicly disclosed
Mar 22, 2021
Last updated
Oct 9, 2026
Weakness Type
- CWE-434 Unrestricted Upload of File with Dangerous Type
- CWE-502 Deserialization of Untrusted Data
References
- advisoryhttp://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-27221
- advisoryhttp://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-22696
- advisoryRHSA-2021:1354
- advisoryRHSA-2021:2139
- advisoryRHSA-2021:2475
FAQ
Common Questions.
XStream is a Java library to serialize objects to XML and back again.
Affected: Activemq (Apache) versions 5.16.0, 5.16.1; Jmeter (Apache); Oncommand Insight (Netapp), among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Activemq 5.15.14, Jmeter 5.5, com.thoughtworks.xstream:xstream 1.4.16.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.
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