{"id":"CVE-2021-21344","published":"2021-03-22T23:40:29Z","modified":"2026-10-07T18:48:03Z","title":"XStream is vulnerable to an Arbitrary Code Execution attack","vendor":"x-stream","product":"xstream","tier":"core","eol":null,"affectedVersions":[{"vendor":"x-stream","product":"xstream","versions":["< 1.4.16"]}],"description":{"text":"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.","provenance":"source","from":"CVE.org"},"summary":{"text":"The XStream Java library for serializing objects to XML and back has an arbitrary code execution flaw caused by deserialization of untrusted data, affecting versions before 1.4.16 when relying on the default blacklist of its security framework. A remote attacker who can supply crafted input to the processed XML stream can cause arbitrary code to be loaded and executed from a remote host, and exploitation requires user interaction.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-29T07:22:34Z"},"cvss":{"score":5.3,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N","provenance":"source","from":"CVE.org CNA"},"epss":{"score":0.7598,"percentile":0.99528,"date":"2026-10-29","provenance":"source"},"kev":null,"vulncheckKev":null,"exploited":false,"otx":{"pulseCount":0,"pulses":[],"provenance":"machine"},"cwes":[{"id":"CWE-434","name":"Unrestricted Upload of File with Dangerous Type"},{"id":"CWE-502","name":"Deserialization of Untrusted Data"}],"references":[{"url":"https://x-stream.github.io/security.html#workaround","tags":["x_refsource_MISC"]},{"url":"http://x-stream.github.io/changes.html#1.4.16","tags":["x_refsource_MISC"]},{"url":"https://github.com/x-stream/xstream/security/advisories/GHSA-59jw-jqf4-3wq3","tags":["x_refsource_CONFIRM"]},{"url":"https://x-stream.github.io/CVE-2021-21344.html","tags":["x_refsource_MISC"]},{"url":"https://lists.debian.org/debian-lts-announce/2021/04/msg00002.html","tags":["mailing-list","x_refsource_MLIST"]},{"url":"https://lists.apache.org/thread.html/r9ac71b047767205aa22e3a08cb33f3e0586de6b2fac48b425c6e16b0%40%3Cdev.jmeter.apache.org%3E","tags":["mailing-list","x_refsource_MLIST"]},{"url":"https://lists.apache.org/thread.html/r8244fd0831db894d5e89911ded9c72196d395a90ae655414d23ed0dd%40%3Cusers.activemq.apache.org%3E","tags":["mailing-list","x_refsource_MLIST"]},{"url":"https://security.netapp.com/advisory/ntap-20210430-0002/","tags":["x_refsource_CONFIRM"]},{"url":"https://www.oracle.com//security-alerts/cpujul2021.html","tags":["x_refsource_MISC"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP/","tags":["vendor-advisory","x_refsource_FEDORA"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB/","tags":["vendor-advisory","x_refsource_FEDORA"]},{"url":"https://www.oracle.com/security-alerts/cpuoct2021.html","tags":["x_refsource_MISC"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7/","tags":["vendor-advisory","x_refsource_FEDORA"]},{"url":"https://www.debian.org/security/2021/dsa-5004","tags":["vendor-advisory","x_refsource_DEBIAN"]},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","tags":["x_refsource_MISC"]}],"techniques":[],"reports":[],"affected":[{"ecosystem":"Maven","package":"com.thoughtworks.xstream:xstream","vulnerableRanges":["<1.4.16"],"patched":["1.4.16"],"from":["GHSA-59jw-jqf4-3wq3"],"provenance":"source"}],"advisories":[{"id":"GHSA-59jw-jqf4-3wq3","url":"https://github.com/advisories/GHSA-59jw-jqf4-3wq3","severity":"MODERATE","ecosystem":"Maven","package":"com.thoughtworks.xstream:xstream","vulnerableRanges":["<1.4.16"],"patched":["1.4.16"],"provenance":"source","from":"GHSA"}],"euvd":{"id":"EUVD-2021-0609","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-0609","exploited":false,"exploitedSince":null,"provenance":"source"},"exploits":[],"exploitSources":null,"exploitRefs":[],"flow":[],"timeline":[{"date":"2021-03-22","kind":"published","label":"Published (CVE.org)","url":"https://www.cve.org/CVERecord?id=CVE-2021-21344","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":null},"priority":{"score":23.6,"factors":[{"name":"In a KEV catalog","points":0.0,"detail":"not listed"},{"name":"Recent KEV listing","points":0.0,"detail":"not listed"},{"name":"Known ransomware use","points":0.0,"detail":"not known"},{"name":"EPSS percentile","points":19.91,"detail":"percentile 0.9953"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":0.0,"detail":"none found"},{"name":"Mentioned in OTX pulses","points":0.0,"detail":"0 pulses"},{"name":"CVSS severity","points":3.71,"detail":"base score 5.3"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}