Disclosure summary
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.
Source-reported weakness categories
CWE-918
Source-specific records & product guidance
Sources retain their own attribution and scoring. Follow the original record to confirm affected versions, fixed releases, and configuration conditions.
NIST National Vulnerability Database · NVD-CVE-2020-26258
Open original source · Updated Oct 07, 2026
Only CPE matches marked vulnerable=true are indexed. AND/OR platform conditions must be checked in the original NVD record.
| Vendor | Product / association | Version / bounds |
|---|---|---|
| apache | struts | * {"versionEndExcluding":"6.0.0"} |
| xstream | xstream | * {"versionEndExcluding":"1.4.15"} |
| debian | debian_linux | 9.0 |
| debian | debian_linux | 10.0 |
| fedoraproject | fedora | 33 |
| fedoraproject | fedora | 34 |
| fedoraproject | fedora | 35 |
Original records & references
- NIST NVD record
- CVE Program record
- github.com — Mitigation, Third Party Advisory
- lists.apache.org — Issue Tracking, Mailing List
- lists.debian.org — Mailing List, Third Party Advisory
- lists.fedoraproject.org — Mailing List
- lists.fedoraproject.org — Mailing List
- lists.fedoraproject.org — Mailing List
- security.netapp.com — Third Party Advisory
- www.debian.org — Third Party Advisory
- x-stream.github.io — Exploit, Mitigation, Third Party Advisory
- github.com — Mitigation, Third Party Advisory
- lists.apache.org — Issue Tracking, Mailing List
- lists.debian.org — Mailing List, Third Party Advisory
- lists.fedoraproject.org — Mailing List
- lists.fedoraproject.org — Mailing List
- lists.fedoraproject.org — Mailing List
- security.netapp.com — Third Party Advisory
- www.debian.org — Third Party Advisory
- x-stream.github.io — Exploit, Mitigation, Third Party Advisory
PUBLISHED 2020-12-15T20:15:12-05:00
MODIFIED 2026-10-07T15:17:17-04:00
INGESTED 2026-10-08T12:30:34-04:00