{"id":"CVE-2021-21351","published":"2021-03-22T23:45:15Z","modified":"2026-10-07T18:48:37Z","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 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":null,"cvss":{"score":5.4,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:C/C:N/I:H/A:N","provenance":"source","from":"CVE.org CNA"},"epss":{"score":0.82136,"percentile":0.99654,"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-hrcp-8f3q-4w2c","tags":["x_refsource_CONFIRM"]},{"url":"https://x-stream.github.io/CVE-2021-21351.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-hrcp-8f3q-4w2c"],"provenance":"source"}],"advisories":[{"id":"GHSA-hrcp-8f3q-4w2c","url":"https://github.com/advisories/GHSA-hrcp-8f3q-4w2c","severity":"MODERATE","ecosystem":"Maven","package":"com.thoughtworks.xstream:xstream","vulnerableRanges":["<1.4.16"],"patched":["1.4.16"],"provenance":"source","from":"GHSA"}],"euvd":{"id":"EUVD-2021-0671","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-0671","exploited":false,"exploitedSince":null,"provenance":"source"},"exploits":[],"exploitSources":{"nuclei":[{"id":"CVE-2021-21351","name":"XStream <1.4.16 - Remote Code Execution","severity":"critical","path":"http/cves/2021/CVE-2021-21351.yaml","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-21351.yaml"}],"provenance":"source"},"exploitRefs":[],"flow":[],"timeline":[{"date":"2021-03-22","kind":"published","label":"Published (CVE.org)","url":"https://www.cve.org/CVERecord?id=CVE-2021-21351","provenance":"source"}],"speed":{"daysToPublicExploit":null,"firstExploitFrom":null,"daysToKev":null},"priority":{"score":28.7,"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":19.93,"detail":"percentile 0.9965"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"1 nuclei template"},{"name":"Mentioned in OTX pulses","points":0.0,"detail":"0 pulses"},{"name":"CVSS severity","points":3.78,"detail":"base score 5.4"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]}}