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HIGH

CVE-2021-43859

CVSS v3

7.5

HIGH

EPSS Score

7.9 %

exploit probability, as of 2026-10-19

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

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

  • com.thoughtworks.xstream:xstreamMavenall versions · fixed in 1.4.19
  • jenkinsBitnamiall versions · fixed in 2.319.3

Vendor advisories

  • CVE-2021-43859 Red Hat Product Security4 products fixed · 19 known affected

    xstream: Injecting highly recursive collections or maps can cause a DoS

    xstream as a component of Red Hat BPM Suite 6 · xstream as a component of Red Hat Data Grid 8 · xstream as a component of Red Hat Decision Manager 7

  • RHSA-2022:5606 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Integration Camel Extensions for Quarkus 2.7 security update

  • RHSA-2022:5532 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Fuse 7.11.0 release and security update

  • RHSA-2022:1420 Red Hat Product Security2 products fixed

    Red Hat Security Advisory: OpenShift Container Platform 3.11.685 security and bug fix update

Full record on NVD

Description

XStream is an open source java library to serialize objects to XML and back again. Versions prior to 1.4.19 may allow a remote attacker to allocate 100% CPU time on the target system depending on CPU type or parallel execution of such a payload resulting in a denial of service only by manipulating the processed input stream. XStream 1.4.19 monitors and accumulates the time it takes to add elements to collections and throws an exception if a set threshold is exceeded. Users are advised to upgrade as soon as possible. Users unable to upgrade may set the NO_REFERENCE mode to prevent recursion. See GHSA-rmr5-cpv2-vgjf for further details on a workaround if an upgrade is not possible.

Technical details

Published
2022-02-01

Frequently asked questions

What is CVE-2021-43859?

XStream is an open source java library to serialize objects to XML and back again. Versions prior to 1.4.19 may allow a remote attacker to allocate 100% CPU time on the target system depending on CPU type or parallel execution of such a payload resulting in a denial of service only by manipulating the processed input stream. XStream 1.4.19 monitors and accumulates the time it takes to add elements to collections and throws an exception if a set threshold is exceeded. Users are advised to upgrade as soon as possible. Users unable to upgrade may set the NO_REFERENCE mode to prevent recursion. See GHSA-rmr5-cpv2-vgjf for further details on a workaround if an upgrade is not possible.

Is CVE-2021-43859 actively exploited?

Active exploitation of CVE-2021-43859 has not been confirmed. Its EPSS score was 7.9% on 2026-10-19, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-43859?

CVE-2021-43859 has a CVSS v3 base score of 7.5 (HIGH severity).

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