CVE-2020-26258

unknown
Published 2020-12-21 · Modified 2026-03-13
CVSS v3
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N
CVSS v2
VIR risk

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.

Predictions

Exploit likelihood
30%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2020-26258

vendor Authored 2026-05-27

Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2020-26258.html

OS impact

OSVersionStatusFixed in
suse slesaffected
debian debianbookwormfixed1.4.15-1
debian debianbullseyefixed1.4.15-1
debian debianforkyfixed1.4.15-1
debian debiansidfixed1.4.15-1
debian debiantrixiefixed1.4.15-1

Package impact

EcosystemPackageVulnerableFixed
java Mavencom.thoughtworks.xstream:xstream<1.4.151.4.15

References

Verify integrity in audit chain (admin only). AS-IS.