WaratekVRT Sign in

CVE-2020-26259 XStream

Affected softwareXStream
Severity6.8 Medium CVSS 3.1 3 scores
Fixed in1.4.15
WeaknessOS command injection (CWE-78)
Published16 Dec 2020
Updated7 Oct 2026

Description

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.15, is vulnerable to an Arbitrary File Deletion on the local host when unmarshalling. The vulnerability may allow a remote attacker to delete arbitrary know files on the host as log as the executing process has sufficient rights 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 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.

Exploitation status

Proof of concept only

A proof of concept exists, but no reviewed exploit catalogue lists this CVE.

  • CISA KEV not listed
  • VulnCheck KEV not listed
  • CISA Vulnrichment exploitation: none
  • Indexed PoC 2 indexed Published artifacts you can open, in GitHub PoC; first seen 2020-12-13.
  • EPSS 82% chance in 30 days A model's forecast, not a report of exploitation. Higher than 99.7% of all scored CVEs.

1 of these are GitHub repositories with fewer than 5 stars. They are listed for reference and don't count toward the exploitation status above.

IndexArtifactStarsFirst seen
GitHub PoC CVE-2020-26259: XStream is vulnerable to an Arbitrary File Deletion on the local host when unmarshalling as long as the executing process has sufficient rights. 25 2020-12-13
GitHub PoC CVE-2020-26259 &&XStream Arbitrary File Delete 1 2021-01-22

Waratek protection

Protected by Waratek

Waratek has a rule that blocks attacks on this vulnerability.

Decided by A vulnerability class already blocked by an ARMR security rule
Finding Protected by Waratek's ARMR command-injection security rule, which blocks this class of attack at the JVM level without a rule written for this CVE specifically. The CVE's weakness is CWE-78: OS Command Injection.
Candidate fix https://github.com/x-stream/xstream/security/advisories/GHSA-jfvx-7wrx-43fh : the maintainers' own security advisory: names the version that fixes it, so the fix is the difference between two releases

How to mitigate CVE-2020-26259

Upgrade XStream to 1.4.15 or later. Until you can, Waratek RASP blocks exploitation with its process rule. It runs inside the Java application, with no code changes.

Waratek RASP Runtime protection for Java applications

CVSS

6.8 MEDIUM v3.1 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N 3 metrics

We show the highest score from the newest CVSS version. Scores from different versions can't be compared, and the first score listed is sometimes a 0.0 placeholder.

VersionScoreBandVectorAssignerType
CVSS 3.1 6.8 MEDIUM CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N security-advisories@github.com Secondary published
CVSS 3.1 6.8 MEDIUM CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:H/A:N NVD Primary
CVSS 2.0 6.4 none AV:N/AC:L/Au:N/C:N/I:P/A:P NVD Primary

Affected software and releases

Maven packages

Affected and fixed versions, from OSV.dev
PackageIntroducedFixedLast affected
com.thoughtworks.xstream:xstream 0 1.4.15 unbounded

Products and versions

5 products, 8 version entries
SourceVendorProductSchemeAffected versions
nvd apache struts generic < 6.0.0
osv com.thoughtworks.xstream xstream generic < 1.4.15
nvd debian debian linux generic 9.0 · 10.0
nvd fedoraproject fedora generic 33 · 34 · 35
nvd xstream xstream generic < 1.4.15

References

URLTags
https://github.com/x-stream/xstream/security/advisories/GHSA-jfvx-7wrx-43fh advisory
https://github.com/x-stream/xstream PACKAGE
https://lists.apache.org/thread.html/r97993e3d78e1f5389b7b172ba9f308440830ce5f051ee62714a0aa34@%3Ccommits.struts.apache.org%3E WEB
https://lists.debian.org/debian-lts-announce/2020/12/msg00042.html WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7 WEB
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB WEB
https://security.netapp.com/advisory/ntap-20210409-0005 WEB
https://www.debian.org/security/2021/dsa-4828 WEB
https://x-stream.github.io/CVE-2020-26259.html WEB

Timeline

Published2020-12-16By the CVE Program.
NVD record modified2026-10-07NVD's own last-modified date for this record.