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Public proof of conceptFix available

CVE-2020-26258

A public proof of concept exists; no exploitation attested.

  • Published2020-12-16
  • Fixed in1.4.15
  • WeaknessCWE-918

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2020-12-1601:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-11-03 21:37 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-26258?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-26258?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV
Xstream
BranchAffectedFixed in
1.4< 1.4.151.4.15
Fedoraproject fedora
BranchAffectedFixed in
33.x= 33no fix published
34.x= 34no fix published
35.x= 35no fix published
Debian debian linux
BranchAffectedFixed in
9.0= 9.0no fix published
10.0= 10.0no fix published

1 more product in the sources.

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Products declared by the CNA1 product

As GitHub_M, the CNA that assigned this CVE, declared them in the CVE record; versions as written.

  • x-stream xstream
    Affected
    • = < 1.4.15no fix stated

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2025-01-15

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • cobblerSUSE:Manager Server Module 4.1all versions · fixed in 3.0.0+git20190806.32c4bae0-5.6.4
  • grafana-formulaSUSE:Manager Server Module 4.1all versions · fixed in 0.4.0-3.6.2
  • hadoop-fips-3.3.6Chainguardall versions · no fixed version listed
  • libxstream-javaUbuntu:Pro:16.04:LTSall versions · fixed in 1.4.8-1ubuntu0.1+esm3
  • libxstream-javaUbuntu:Pro:14.04:LTSall versions · fixed in 1.4.7-1ubuntu0.1+esm2
  • libxstream-javaUbuntu:20.04:LTSall versions · fixed in 1.4.11.1-1ubuntu0.1
  • libxstream-javaUbuntu:20.04:LTSall versions · fixed in 1.4.11.1-1ubuntu0.2
  • libxstream-javaUbuntu:18.04:LTSall versions · fixed in 1.4.11.1-1~18.04.1

38 more package ranges on OSV.dev

Vendor advisories

  • CVE-2020-26258 Red Hat Product Security6 products fixed · 13 known affected

    XStream: Server-Side Forgery Request vulnerability can be activated when unmarshalling

    xstream as a component of Red Hat BPM Suite 6 · xstream as a component of Red Hat Enterprise Linux 7 · xstream-javadoc as a component of Red Hat Enterprise Linux 7 · +10 more

  • RHSA-2021:4767 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Integration Camel Extensions for Quarkus GA security update

  • RHSA-2021:3205 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Integration Camel-K 1.4 release and security update

  • RHSA-2021:3140 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Fuse 7.9.0 release and security update

  • RHSA-2021:2476 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Decision Manager 7.11.0 security update

  • RHSA-2021:2475 Red Hat Product Security1 product fixed

    Red Hat Security Advisory: Red Hat Process Automation Manager 7.11.0 security update

1 more advisory

Full record on NVD

Fix

  1. Update Xstream to 1.4.15
  2. Vendor fix Red Hat Product Security RHSA-2021:4767 · 1 productBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://access.redhat.com/articles/11258
  3. Vendor fix Red Hat Product Security RHSA-2021:3140 · 1 productBefore applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on. Installation instructions are available from the Fuse 7.9.0 product documentation page: https://access.redhat.com/documentation/en-us/red_hat…
  4. Vendor fix Red Hat Product Security RHSA-2021:2476 · 1 productFor on-premise installations, before applying the update, back up your existing installation, including all applications, configuration files, databases and database settings, and so on. It is recommended to halt the server by stopping the JBoss Application Server process before installing this up…
  5. Vendor fix Red Hat Product Security RHSA-2021:2139 · 1 productRefer to the Data Grid 8.2 Upgrade Guide for instructions on upgrading to this version. The References section of this erratum contains a download link (you must log in to download the update).
  6. Workaround from the vendor Red Hat Product Security RHSA-2021:4767 · 1 productAs recommended, use XStream's security framework to implement a whitelist for the allowed types. Users of XStream 1.4.14 who insist to use XStream default blacklist - despite that clear recommendation - can simply add two lines to XStream's setup code: xstream.denyTypes(new String[]{ "jdk.nashorn…
  7. No fix available, says the vendor Red Hat Product Security CVE-2020-26258 · 2 productsAffected

Advisories and patches

Detection

read 2026-11-02 22:42 UTC
Nuclei template
available
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
2 repositories, unverifiedAl1ex/CVE-2020-26258cuijiung/xstream-CVE-2020-26258
PoC-in-GitHub
Metasploit modules
none listed
Metasploit Framework

Sources

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N
Published
2020-12-16
Last Modified
2026-10-07
NVD status
Analyzed
GitHub Advisory
GHSA-4cch-wxpw-8p28

Frequently asked questions

What is CVE-2020-26258?

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.

Is CVE-2020-26258 actively exploited?

Active exploitation of CVE-2020-26258 has not been confirmed. Its EPSS score was 81.8% on 2026-11-03, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-26258?

CVE-2020-26258 has a CVSS v3 base score of 7.7 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N.

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