CVE-2021-21348
highpriority · track · 35EPSS 0.138 · 97 %ileDEEURUUSEPSS · scored 2026-10-27
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 occupy a thread that consumes maximum CPU time and will never return. 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.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 5.3–7.8
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (103)
Products and version ranges known to be affected.
advisories (3)
Vendor and ecosystem advisories describing this.
- WID-SEC-W-2026-0180Dell Data Protection Advisor: Mehrere SchwachstellenDeutsch2026-01-20csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Dell Data Protection Advisor ausnutzen, um beliebigen Code auszuführen, einen Denial-of-Service-Zustand zu erzeugen, Sicherheitsmaßnahmen zu umgehen und nicht näher spezifizierte Angriffe zu starten.
- GHSA-56p8-3fh9-4cvqXStream is vulnerable to an attack using Regular Expression for a Denial of Service (ReDos)2021-03-22ghsa · osvUS
### Impact The vulnerability may allow a remote attacker to occupy a thread that consumes maximum CPU time and will never return. No user is affected, who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. ### Patches If you rely on XStream's default blacklist of the [Security Framework](https://x-stream.github.io/security.html#framework), you will have to use at least version 1.4.16. ### Workarounds See [workarounds](https://x-stream.github.io/security.html#workaround) for the different versions covering all CVEs. ### References See full information about the nature of the vulnerability and the steps to reproduce it in XStream's documentation for [CVE-2021-21348](https://x-stream.github.io/CVE-2021-21348.html). ### Credits The vulnerability was discovered and reported by threedr3am. ### For more information If you have any questions or comments about this advisory: * Open an issue in [XStream](https://github.com/x-stream/xstream/issues) * Contact us at [XStream Google Group](https://groups.google.com/group/xstream-user)
- BIT-activemq-2021-21348XStream is vulnerable to an attack using Regular Expression for a Denial of Service (ReDos)2025-12-03vendor · osvUS
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 occupy a thread that consumes maximum CPU time and will never return. 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.
also known as (6)
Other names and identifiers for this entity.
sources
Which sources assert this record, and when.
references (69)
External citations — patches, advisories, analysis.
- http://x-stream.github.io/changes.html#1.4.16cnnvd
- https://github.com/x-stream/xstream/security/advisories/GHSA-56p8-3fh9-4cvqcnnvd
- https://lists.apache.org/thread.html/r8244fd0831db894d5e89911ded9c72196d395a90ae655414d23ed0dd@%3Cusers.activemq.apache.org%3Ecnnvd
- https://lists.apache.org/thread.html/r9ac71b047767205aa22e3a08cb33f3e0586de6b2fac48b425c6e16b0@%3Cdev.jmeter.apache.org%3Ecnnvd
- https://lists.debian.org/debian-lts-announce/2021/04/msg00002.htmlcnnvd
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP/cnnvd
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7/cnnvd
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB/cnnvd
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