CVE-2020-26258Server-Side Forgery Request can be activated unmarshalling with XStream
- 6.3MediumCVSS base score
- 81.8%Exploitation in 30 daysEPSS · top 0.3% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- 1Public exploitsMetasploit, Nuclei and Exploit-DB
Description
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. The public collections list a Nuclei template for it.
Show the exploits1
Nuclei templates1 template
- XStream <1.4.15 - Server-Side Request Forgery (Nuclei template) (opens in a new tab)
http/cves/2020/CVE-2020-26258.yamlSeverity high
Modules, templates and exploits as listed by the Metasploit Framework (BSD-3-Clause), ProjectDiscovery's Nuclei templates (MIT) and the Exploit Database (GPLv2), read once a day. Where the data comes from
Timeline
ID reserved
By GitHub_M
- 3 months later
· 3 months later
Published
- 6 years later
· 6 years later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_MCNA (assigner) | 3.1 | Medium6.3 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N |
| NVDNVD · Analyzed | 3.1 | High7.7 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N |
- EPSS (exploitation in 30 days)
- 81.8% · top 0.3% of all CVEs (12 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.3.
Affected products
Affected packages
From reviewed advisories of the GitHub Advisory Database.
- Mavencom.thoughtworks.xstream:xstreamGHSA-4cch-wxpw-8p28 (opens in a new tab)
References
References14
- https://github.com/x-stream/xstream/security/advisories/GHSA-4cch-wxpw-8p28 (opens in a new tab)x_refsource_CONFIRMx_transferred
- https://lists.apache.org/thread.html/r97993e3d78e1f5389b7b172ba9f308440830ce5f051ee62714a0aa34@%3Ccommits.struts.apache.org%3E (opens in a new tab)x_refsource_MISC
- https://lists.debian.org/debian-lts-announce/2020/12/msg00042.html (opens in a new tab)x_refsource_MISCmailing-listx_refsource_MLISTx_transferred
- https://lists.fedoraproject.org/archives/list/[email protected]/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP (opens in a new tab)x_refsource_MISC
- https://lists.fedoraproject.org/archives/list/[email protected]/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7 (opens in a new tab)x_refsource_MISC
- https://lists.fedoraproject.org/archives/list/[email protected]/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB (opens in a new tab)x_refsource_MISC
- https://security.netapp.com/advisory/ntap-20210409-0005 (opens in a new tab)x_refsource_MISC
- https://www.debian.org/security/2021/dsa-4828 (opens in a new tab)x_refsource_MISCvendor-advisoryx_refsource_DEBIANx_transferred
- https://x-stream.github.io/CVE-2020-26258.html (opens in a new tab)x_refsource_MISCx_transferred
- [struts-commits] 20201221 [struts] branch master updated: Upgrades XStream to version 1.4.15 to address CVE-2020-26258, CVE-2020-26259 (opens in a new tab)mailing-listx_refsource_MLISTx_transferred
- https://security.netapp.com/advisory/ntap-20210409-0005/ (opens in a new tab)x_refsource_CONFIRMx_transferred
- FEDORA-2021-fbad11014a (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- FEDORA-2021-d894ca87dc (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
- FEDORA-2021-5e376c0ed9 (opens in a new tab)vendor-advisoryx_refsource_FEDORAx_transferred
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2020-1481 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisory GHSA-4cch-wxpw-8p28 (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2020-26258)Record last updated .