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Public proof of conceptFix available

CVE-2021-21351

A public proof of concept exists; no exploitation attested.

  • Published2021-03-23
  • Fixed in1.4.16
  • WeaknessCWE-434 · CWE-502

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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 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.

Timeline

dates in UTC
  1. 2021-03-2300:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 15:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-21351?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-21351?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Xstream
BranchAffectedFixed in
1.4< 1.4.161.4.16
Apache activemq
BranchAffectedFixed in
5.15< 5.15.145.15.14
5.16= 5.16.0no fix published
5.16= 5.16.1no fix published
5.16≥ 5.16.0, ≤ 5.16.0no fix published
5.16≥ 5.16.1, ≤ 5.16.1no fix published
Oracle communications unified inventory management
BranchAffectedFixed in
7.3= 7.3.2no fix published
7.3= 7.3.4no fix published
7.3= 7.3.5no fix published
7.4= 7.4.0no fix published
7.4= 7.4.1no fix published

13 more products in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • x-stream xstream
    Affected
    • = < 1.4.16no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2022-02-07

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • hadoop-fips-3.3.6Chainguardall versions · no fixed version listed
  • libxstream-javaUbuntu:Pro:16.04:LTSall versions · fixed in 1.4.8-1ubuntu0.1+esm3
  • libxstream-javaUbuntu:Pro:14.04:LTSall versions · fixed in 1.4.7-1ubuntu0.1+esm2
  • libxstream-javaUbuntu:20.04:LTSall versions · fixed in 1.4.11.1-1ubuntu0.2
  • libxstream-javaUbuntu:18.04:LTSall versions · fixed in 1.4.11.1-1~18.04.2
  • libxstream-javaDebian:14all versions · fixed in 1.4.15-2
  • libxstream-javaDebian:13all versions · fixed in 1.4.15-2
  • libxstream-javaDebian:12all versions · fixed in 1.4.15-2

10 more package ranges on OSV.dev

Vendor advisories

  • CVE-2021-21351 Red Hat Product Security6 products fixed · 14 known affected

    XStream: allow a remote attacker to load and execute arbitrary code from a remote host only by manipulating the processed input stream

    xstream as a component of Red Hat BPM Suite 6 · xstream as a component of Red Hat Enterprise Linux 7 · xstream-javadoc as a component of Red Hat Enterprise Linux 7 · +11 more

  • RHSA-2021:5134 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Fuse 7.10.0 release and security update

  • RHSA-2021:4918 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Integration Camel-K 1.6 release and security update

  • RHSA-2021:4767 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Integration Camel Extensions for Quarkus GA security update

  • RHSA-2021:2476 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Decision Manager 7.11.0 security update

  • RHSA-2021:2475 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Process Automation Manager 7.11.0 security update

1 more advisory

Full record on NVD

Fix

  1. Update Xstream to 1.4.16
  2. Vendor fix Red Hat Product Security RHSA-2021:5134 · 1 productBefore applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on. Installation instructions are available from the Fuse 7.10.0 product documentation page: https://access.redhat.com/documentation/en-us/red_ha…
  3. Vendor fix Red Hat Product Security RHSA-2021:4918 · 1 productBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  4. Vendor fix Red Hat Product Security RHSA-2021:2476 · 1 productFor on-premise installations, before applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on. It is recommended to halt the server by stopping the JBoss Application Server process before installing this up…
  5. Vendor fix Red Hat Product Security RHSA-2021:2139 · 1 productRefer to the Data Grid 8.2 Upgrade Guide for instructions on upgrading to this version. The References section of this erratum contains a download link (you must log in to download the update).
  6. No fix available, says the vendor Red Hat Product Security CVE-2021-21351 · 2 productsAffected
  7. No fix planned, says the vendor Red Hat Product Security CVE-2021-21351 · 12 productsOut of support scope

Advisories and patches

Detection

read 2026-11-02 22:42 UTC
Nuclei template
available
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H
Published
2021-03-23
Last Modified
2026-10-07
NVD status
Analyzed
GitHub Advisory
GHSA-hrcp-8f3q-4w2c

Frequently asked questions

What is CVE-2021-21351?

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability 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.

Is CVE-2021-21351 actively exploited?

Active exploitation of CVE-2021-21351 has not been confirmed. Its EPSS score was 82.1% on 2026-11-02, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-21351?

CVE-2021-21351 has a CVSS v3 base score of 9.1 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H.

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Sources for this record