{"id":"CVE-2020-26258","published":"2020-12-16T01:05:22Z","modified":"2026-10-07T18:41:30Z","title":"Server-Side Forgery Request can be activated unmarshalling with XStream","vendor":"x-stream","product":"xstream","tier":"core","eol":null,"affectedVersions":[{"vendor":"x-stream","product":"xstream","versions":["< 1.4.15"]}],"description":{"text":"XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.15, a Server-Side Forgery Request vulnerability can be activated when unmarshalling. The vulnerability may allow a remote attacker to request data from internal resources that are not publicly available only by manipulating the processed input stream. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.15. The reported vulnerability does not exist if running Java 15 or higher. No user is affected who followed the recommendation to setup XStream's Security Framework with a whitelist! Anyone relying on XStream's default blacklist can immediately switch to a whilelist for the allowed types to avoid the vulnerability. Users of XStream 1.4.14 or below who still want to use XStream default blacklist can use a workaround described in more detailed in the referenced advisories.","provenance":"source","from":"CVE.org"},"summary":{"text":"A Server-Side Request Forgery flaw in the XStream Java library (product xstream, versions before 1.4.15) can be triggered during unmarshalling of XML data.","provenance":"ai","model":"claude-haiku-5-5","generatedAt":"2026-10-29T07:13:32Z"},"cvss":{"score":6.3,"severity":"MEDIUM","version":"3.1","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N","provenance":"source","from":"CVE.org CNA"},"epss":{"score":0.81817,"percentile":0.99645,"date":"2026-10-29","provenance":"source"},"kev":null,"vulncheckKev":null,"exploited":false,"otx":{"pulseCount":0,"pulses":[],"provenance":"machine"},"cwes":[{"id":"CWE-918","name":"Server-Side Request Forgery"}],"references":[{"url":"https://github.com/x-stream/xstream/security/advisories/GHSA-4cch-wxpw-8p28","tags":["x_refsource_CONFIRM"]},{"url":"https://lists.apache.org/thread.html/r97993e3d78e1f5389b7b172ba9f308440830ce5f051ee62714a0aa34@%3Ccommits.struts.apache.org%3E","tags":["x_refsource_MISC"]},{"url":"https://lists.debian.org/debian-lts-announce/2020/12/msg00042.html","tags":["x_refsource_MISC"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP","tags":["x_refsource_MISC"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7","tags":["x_refsource_MISC"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB","tags":["x_refsource_MISC"]},{"url":"https://security.netapp.com/advisory/ntap-20210409-0005","tags":["x_refsource_MISC"]},{"url":"https://www.debian.org/security/2021/dsa-4828","tags":["x_refsource_MISC"]},{"url":"https://x-stream.github.io/CVE-2020-26258.html","tags":["x_refsource_MISC"]},{"url":"https://lists.apache.org/thread.html/r97993e3d78e1f5389b7b172ba9f308440830ce5f051ee62714a0aa34%40%3Ccommits.struts.apache.org%3E","tags":["mailing-list","x_refsource_MLIST","x_transferred"]},{"url":"https://security.netapp.com/advisory/ntap-20210409-0005/","tags":["x_refsource_CONFIRM","x_transferred"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP/","tags":["vendor-advisory","x_refsource_FEDORA","x_transferred"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB/","tags":["vendor-advisory","x_refsource_FEDORA","x_transferred"]},{"url":"https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7/","tags":["vendor-advisory","x_refsource_FEDORA","x_transferred"]}],"techniques":[],"reports":[],"affected":[{"ecosystem":"Maven","package":"com.thoughtworks.xstream:xstream","vulnerableRanges":["<1.4.15"],"patched":["1.4.15"],"from":["GHSA-4cch-wxpw-8p28"],"provenance":"source"}],"advisories":[{"id":"GHSA-4cch-wxpw-8p28","url":"https://github.com/advisories/GHSA-4cch-wxpw-8p28","severity":"MODERATE","ecosystem":"Maven","package":"com.thoughtworks.xstream:xstream","vulnerableRanges":["<1.4.15"],"patched":["1.4.15"],"provenance":"source","from":"GHSA"}],"euvd":{"id":"EUVD-2020-1481","url":"https://euvd.enisa.europa.eu/vulnerability/EUVD-2020-1481","exploited":false,"exploitedSince":null,"provenance":"source"},"exploits":[],"exploitSources":{"pocGithub":{"count":1,"skipped":1,"earliest":"2021-01-22","earliestUrl":"https://github.com/Al1ex/CVE-2020-26258","repos":[{"name":"Al1ex/CVE-2020-26258","url":"https://github.com/Al1ex/CVE-2020-26258","stars":0,"created":"2021-01-22"}]},"nuclei":[{"id":"CVE-2020-26258","name":"XStream <1.4.15 - Server-Side Request Forgery","severity":"high","path":"http/cves/2020/CVE-2020-26258.yaml","url":"https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2020/CVE-2020-26258.yaml"}],"first":{"date":"2021-01-22","source":"PoC-in-GitHub","url":"https://github.com/Al1ex/CVE-2020-26258"},"provenance":"source"},"exploitRefs":[],"flow":[],"timeline":[{"date":"2020-12-16","kind":"published","label":"Published (CVE.org)","url":"https://www.cve.org/CVERecord?id=CVE-2020-26258","provenance":"source"},{"date":"2021-01-22","kind":"exploit-public","label":"First public exploit: PoC-in-GitHub","url":"https://github.com/Al1ex/CVE-2020-26258","provenance":"source"}],"speed":{"daysToPublicExploit":37,"firstExploitFrom":"PoC-in-GitHub","daysToKev":null},"priority":{"score":29.3,"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 0.9964"},{"name":"Named in threat reports","points":0.0,"detail":"0 reports"},{"name":"Public exploit code","points":5.0,"detail":"1 PoC-in-GitHub repo; 1 nuclei template"},{"name":"Mentioned in OTX pulses","points":0.0,"detail":"0 pulses"},{"name":"CVSS severity","points":4.41,"detail":"base score 6.3"},{"name":"End-of-life product","points":0.0,"detail":"supported or unknown"}]},"lineage":{"packageHistory":[{"cve":"CVE-2013-7285","published":"2019-05-15","fixed":"1.4.11","kev":false},{"cve":"CVE-2019-10173","published":"2019-07-23","fixed":"1.4.11","kev":false},{"cve":"CVE-2020-26217","published":"2020-11-16","fixed":"1.4.14-java7","kev":false,"link":{"from":"CVE-2020-26217","to":"CVE-2020-26258","relation":"successor","confidence":"low","kind":"sequence","evidence":[{"kind":"version-step","provenance":"source","package":"Maven:com.thoughtworks.xstream:xstream","fromFixed":"1.4.14-java7","toFixed":"1.4.15","daysApart":30}]}},{"cve":"CVE-2020-26258","published":"2020-12-16","fixed":"1.4.15","kev":false},{"cve":"CVE-2020-26259","published":"2020-12-16","fixed":"1.4.15","kev":false},{"cve":"CVE-2021-21341","published":"2021-03-22","fixed":"1.4.16","kev":false},{"cve":"CVE-2021-21342","published":"2021-03-22","fixed":"1.4.16","kev":false}],"package":"Maven:com.thoughtworks.xstream:xstream"}}