{"id":"CVE-2020-26217","published":"2020-11-16T21:00:18Z","modified":"2026-10-07T18:51:32Z","title":"Remote Code Execution in XStream","vendor":"x-stream","product":"xstream","tier":"core","eol":null,"affectedVersions":[{"vendor":"x-stream","product":"xstream","versions":["< 1.4.14"]}],"description":{"text":"XStream before version 1.4.14 is vulnerable to Remote Code Execution.The vulnerability may allow a remote attacker to run arbitrary shell commands only by manipulating the processed input stream. Only users who rely on blocklists are affected. Anyone using XStream's Security Framework allowlist is not affected. The linked advisory provides code workarounds for users who cannot upgrade. The issue is fixed in version 1.4.14.","provenance":"source","from":"CVE.org"},"summary":{"text":"The XStream Java serialization library, product xstream from vendor x-stream, contains an OS command injection flaw in versions before 1.4.14, where processing of crafted input can lead to arbitrary shell command execution. A remote attacker needs a deployment that relies on XStream's blocklist rather than its allowlist, and the exploit requires the attacker to get a victim to process the malicious input stream, with low privileges and some user interaction involved.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-29T07:13:07Z"},"cvss":{"score":8,"severity":"HIGH","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H","provenance":"source","from":"CVE.org CNA"},"epss":{"score":0.82717,"percentile":0.99667,"date":"2026-10-29","provenance":"source"},"kev":null,"vulncheckKev":null,"exploited":false,"otx":{"pulseCount":0,"pulses":[],"provenance":"machine"},"cwes":[{"id":"CWE-78","name":"Improper Neutralization of Special Elements used in an OS Command"}],"references":[{"url":"https://github.com/x-stream/xstream/security/advisories/GHSA-mw36-7c6c-q4q2","tags":["x_refsource_CONFIRM"]},{"url":"https://x-stream.github.io/CVE-2020-26217.html","tags":["x_refsource_CONFIRM"]},{"url":"https://github.com/x-stream/xstream/commit/0fec095d534126931c99fd38e9c6d41f5c685c1a","tags":["x_refsource_CONFIRM"]},{"url":"https://lists.debian.org/debian-lts-announce/2020/12/msg00001.html","tags":["mailing-list","x_refsource_MLIST"]},{"url":"https://www.debian.org/security/2020/dsa-4811","tags":["vendor-advisory","x_refsource_DEBIAN"]},{"url":"https://lists.apache.org/thread.html/redde3609b89b2a4ff18b536a06ef9a77deb93d47fda8ed28086fa8c3%40%3Cissues.activemq.apache.org%3E","tags":["mailing-list","x_refsource_MLIST"]},{"url":"https://lists.apache.org/thread.html/r826a006fda71cc96fc87b6eca4b5d195f19a292ad36cea501682c38c%40%3Cissues.activemq.apache.org%3E","tags":["mailing-list","x_refsource_MLIST"]},{"url":"https://lists.apache.org/thread.html/r2de526726e7f4db4a7cb91b7355070779f51a84fd985c6529c2f4e9e%40%3Cissues.activemq.apache.org%3E","tags":["mailing-list","x_refsource_MLIST"]},{"url":"https://www.oracle.com/security-alerts/cpuApr2021.html","tags":["x_refsource_MISC"]},{"url":"https://security.netapp.com/advisory/ntap-20210409-0004/","tags":["x_refsource_CONFIRM"]},{"url":"https://www.oracle.com//security-alerts/cpujul2021.html","tags":["x_refsource_MISC"]},{"url":"https://lists.apache.org/thread.html/r7c9fc255edc0b9cd9567093d131f6d33fde4c662aaf912460ef630e9%40%3Ccommits.camel.apache.org%3E","tags":["mailing-list","x_refsource_MLIST"]},{"url":"https://www.oracle.com/security-alerts/cpuoct2021.html","tags":["x_refsource_MISC"]},{"url":"https://www.oracle.com/security-alerts/cpujan2022.html","tags":["x_refsource_MISC"]},{"url":"https://www.oracle.com/security-alerts/cpuapr2022.html","tags":["x_refsource_MISC"]}],"techniques":[],"reports":[],"affected":[{"ecosystem":"Maven","package":"com.thoughtworks.xstream:xstream","vulnerableRanges":["<1.4.14-java7"],"patched":["1.4.14-java7"],"from":["GHSA-mw36-7c6c-q4q2"],"provenance":"source"}],"advisories":[{"id":"GHSA-mw36-7c6c-q4q2","url":"https://github.com/advisories/GHSA-mw36-7c6c-q4q2","severity":"HIGH","ecosystem":"Maven","package":"com.thoughtworks.xstream:xstream","vulnerableRanges":["<1.4.14-java7"],"patched":["1.4.14-java7"],"provenance":"source","from":"GHSA"}],"euvd":{"id":"EUVD-2020-1464","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2020-1464","exploited":false,"exploitedSince":null,"provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":4,"skipped":2,"earliest":"2020-12-08","earliestUrl":"https://github.com/novysodope/CVE-2020-26217-XStream-RCE-POC","repos":[{"name":"novysodope/CVE-2020-26217-XStream-RCE-POC","url":"https://github.com/novysodope/CVE-2020-26217-XStream-RCE-POC","stars":4,"created":"2020-12-08"},{"name":"Al1ex/CVE-2020-26217","url":"https://github.com/Al1ex/CVE-2020-26217","stars":3,"created":"2021-01-22"},{"name":"Kairo-one/CVE-2020-26217-XStream","url":"https://github.com/Kairo-one/CVE-2020-26217-XStream","stars":2,"created":"2025-12-01"},{"name":"epicosy/XStream-1","url":"https://github.com/epicosy/XStream-1","stars":0,"created":"2024-05-31"}]},"nuclei":[{"id":"CVE-2020-26217","name":"XStream <1.4.14 - 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