BlackTreeCVE Intelligence
← Back to the CVE catalogue
Full vulnerability report · 2020
CVE-2020-26258High confidence

Server-Side Forgery Request can be activated unmarshalling with XStream

x-stream · xstream

Official source article: GitHub GHSA-4CCH-WXPW-8P28 ↗. Check the applicable product and release in the original source.

6.3MediumCVSS 3.1
Recommended action
Within 7 days

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:High, raised one band.upgradedsince 7 Oct 2026

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • A structured source references public exploit or proof-of-concept material.
  • EPSS is 81.82% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs x-stream xstream and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 30 daysRemediation target: Within 180 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Distribution package intelligence

Release-specific package status

Debian findings are scoped to the named distribution, release and source package. An absent finding does not mean a package is unaffected.

4 package states
Repository candidate not checked

A published vendor fix does not prove that a matching update is enabled and installable on a particular asset. Confirm the local package candidate before scheduling remediation.

Distribution releaseSource packageVendor stateFixed versionEvidence
Debian trixietrixie · sourcelibxstream-javaVendor fix publishedDebian records a fixed source-package version for this release.1.4.15-1Debian Security Tracker ↗Source updated 23 Oct 2026
Debian bookwormbookworm · sourcelibxstream-javaVendor fix publishedDebian records a fixed source-package version for this release.1.4.15-1Debian Security Tracker ↗Source updated 23 Oct 2026
Debian forkyforky · sourcelibxstream-javaVendor fix publishedDebian records a fixed source-package version for this release.1.4.15-1Debian Security Tracker ↗Source updated 23 Oct 2026
Debian sidsid · sourcelibxstream-javaVendor fix publishedDebian records a fixed source-package version for this release.1.4.15-1Debian Security Tracker ↗Source updated 23 Oct 2026
Open-source package ranges2 source-attributed ranges

These OSV and GitHub advisory ranges apply only to the named package and ecosystem. A listed fixed version is not a universal product patch or proof that an update is installed.

Ecosystem and packageAffected rangeFirst fixed versionEvidence
Mavencom.thoughtworks.xstream:xstreamECOSYSTEM: introduced 0; fixed 1.4.151.4.15OSV record ↗aggregator derived · 10 Sep 2026
mavencom.thoughtworks.xstream:xstream< 1.4.151.4.15GitHub advisory ↗upstream repository advisory · 15 Jan 2025
Direct vendor intelligence

Authoritative vendor CSAF and VEX advisories

Structured product status and remediation from the issuing vendor. Product-state explanations are always visible; large lists can be searched or downloaded.

1 current
CVE-2020-26258 · CSAF 2.0 · revision 3 · finalRed Hat Product SecurityXStream: Server-Side Forgery Request vulnerability can be activated when unmarshalling
13 known affected

The vendor explicitly identifies these products as affected by this CVE.

  • 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
  • xstream.src as a component of Red Hat Enterprise Linux 7
  • xstream as a component of Red Hat Integration Camel K 1
  • xstream as a component of Red Hat Integration Camel Quarkus 1
  • xstream as a component of Red Hat JBoss A-MQ 6
  • xstream as a component of Red Hat JBoss BRMS 6
  • xstream as a component of Red Hat JBoss Data Grid 7
  • xstream as a component of Red Hat JBoss Data Virtualization 6
  • xstream as a component of Red Hat JBoss Fuse 6
  • xstream as a component of Red Hat JBoss Fuse Service Works 6
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.
Remediation
For 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 update; after installing the update, restart the server by starting the JBoss Application Server process. The References section of this erratum contains a download link (you must log in to download the update).
Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2020-1481

No EUVD known-exploited evidence

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.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
6.3 · CVSS 3.1
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

Medium technical severity with public exploit material referenced by a structured source; prioritise exposed affected systems while verifying vendor guidance.

Patch available
01

What, why and how

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.

What

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.

Why

The server follows an attacker-influenced destination, allowing requests to systems or services the attacker cannot reach directly.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

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.

Why

The server follows an attacker-influenced destination, allowing requests to systems or services the attacker cannot reach directly.

How

An attacker operating through a network path may attempt exploitation with low privileges. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Reference recorded

A structured CVE source labels at least one public reference as exploit material. BlackTree has not independently validated that it is safe, reliable or weaponised.

Likely attack path
a network path → Server-Side Request Forgery (SSRF) → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
Low: a basic authenticated account is required
User interaction
None
Attack complexity
High: exploitation depends on specific conditions
Security boundary
Changed: exploitation can affect a different security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-918 ↗

CWE-918: Server-Side Request Forgery (SSRF). The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:N/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACHighAttack complexity: Successful exploitation depends on specific conditions outside the attacker's direct control.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CHighConfidentiality impact: A successful attack can cause a major loss.INoneIntegrity impact: No direct loss is represented by this metric.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkCWE-918Public exploit reference
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2020-1481Official EUVD mapping

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.

Official EUVD record ↗
BSI · German · WID-SEC-2026-0180Dell Data Protection Advisor: Mehrere Schwachstellen

Ein Angreifer kann mehrere Schwachstellen in Dell Data Protection Advisor ausnutzen, um beliebigen Code auszuführen, einen Denial-of-Service-Zustand zu erzeugen, Sicherheitsmaßnahmen zu umgehen und nicht näher spezifizierte Angriffe zu starten.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20201223Security Bulletin 23 Dec 2020

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 23 Dec 2020, published on 23 December 2020. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-943Multiples vulnérabilités dans les produits IBM

d?id=CVE-2020-14061 Référence CVE CVE-2020-14062 https://www.cve.org/CVERecord?id=CVE-2020-14062 Référence CVE CVE-2020-14195 https://www.cve.org/CVERecord?id=CVE-2020-14195 Référence CVE CVE-2020-14314 https://www.cve.org/CVERecord?id=CVE-2020-14314 Référence CVE CVE-2020-14385 https://www.cve.org/CVERecord?id=CVE-2020-14385 Référence CVE CVE-2020-24616 https://www.cve.org/CVERecord?id=CVE-2020-24616 Référence CVE CVE-2020-24750 https://www.cve.org/CVERecord?id=CVE-2020-24750 Référence CVE CVE-2020-25649 https://www.cve.org/CVERecord?id=CVE-2020-25649 Référence CVE CVE-2020-26217 https://www.cve.org/CVERecord?id=CVE-2020-26217 Référence CVE CVE-2020-26258 https://www.cve.org/CVERecord?id=CVE-2020-26258 Référence CVE CVE-2020-26259 https://www.cve.org/CVERecord?id=CVE-2020-26259 Référence CVE CVE-2020-28469 https://www.cve.org/CVERecord?id=CVE-2020-28469 Référence CVE CVE-2020-35728 https://www.cve.org/CVERecord?id=CVE-2020-35728 Référence CVE CVE-2020-36179 https://www.cve.org/CVERecord?id=CVE-2020-36179 Référence CVE CVE-2020-36180 https://www.cve.org/CVERecord?id=CVE-2020-36180 Référence CVE CVE-2020-36181 https://www.cve.org/CVERecord?id=CVE-2020-36181 Référence CVE CVE-2020-36182 https://www.cve.org/CVERecord?id=CVE-2020-36182 Référence CVE CVE-2020-36183 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-490Multiples vulnérabilités dans IBM Spectrum Protect

service à distance et une atteinte à l'intégrité des données. Solution Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation). Documentation Bulletin de sécurité IBM 6466435 du 28 juin 2021 https://www.ibm.com/support/pages/node/6466435 Bulletin de sécurité IBM 6466599 du 28 juin 2021 https://www.ibm.com/support/pages/node/6466599 Bulletin de sécurité IBM 6467281 du 28 juin 2021 https://www.ibm.com/support/pages/node/6467281 Référence CVE CVE-2020-14147 https://www.cve.org/CVERecord?id=CVE-2020-14147 Référence CVE CVE-2020-26217 https://www.cve.org/CVERecord?id=CVE-2020-26217 Référence CVE CVE-2020-26258 https://www.cve.org/CVERecord?id=CVE-2020-26258 Référence CVE CVE-2020-26259 https://www.cve.org/CVERecord?id=CVE-2020-26259 Référence CVE CVE-2020-28476 https://www.cve.org/CVERecord?id=CVE-2020-28476 Référence CVE CVE-2020-7929 https://www.cve.org/CVERecord?id=CVE-2020-7929 Référence CVE CVE-2021-21284 https://www.cve.org/CVERecord?id=CVE-2021-21284 Référence CVE CVE-2021-21285 https://www.cve.org/CVERecord?id=CVE-2021-21285 Référence CVE CVE-2021-21341 https://www.cve.org/CVERecord?id=CVE-2021-21341 Référence CVE CVE-2021-21342 https://www.cve.org/CVERecord?id=CVE-2021-21342 Référence CVE CVE-2021-21343 https://www.cve.org/CVERecord?id=CV

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-407Multiples vulnérabilités dans le noyau Linux de Red Hat

à distance et un contournement de la politique de sécurité. Solution Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation). Documentation Bulletin de sécurité Red Hat RHSA-2021:2106 du 25 mai 2021 https://access.redhat.com/errata/RHSA-2021:2106 Bulletin de sécurité Red Hat RHSA-2021:2139 du 26 mai 2021 https://access.redhat.com/errata/RHSA-2021:2139 Référence CVE CVE-2020-0466 https://www.cve.org/CVERecord?id=CVE-2020-0466 Référence CVE CVE-2020-10771 https://www.cve.org/CVERecord?id=CVE-2020-10771 Référence CVE CVE-2020-12362 https://www.cve.org/CVERecord?id=CVE-2020-12362 Référence CVE CVE-2020-26258 https://www.cve.org/CVERecord?id=CVE-2020-26258 Référence CVE CVE-2020-26259 https://www.cve.org/CVERecord?id=CVE-2020-26259 Référence CVE CVE-2020-28374 https://www.cve.org/CVERecord?id=CVE-2020-28374 Référence CVE CVE-2021-21290 https://www.cve.org/CVERecord?id=CVE-2021-21290 Référence CVE CVE-2021-21295 https://www.cve.org/CVERecord?id=CVE-2021-21295 Référence CVE CVE-2021-21341 https://www.cve.org/CVERecord?id=CVE-2021-21341 Référence CVE CVE-2021-21342 https://www.cve.org/CVERecord?id=CVE-2021-21342 Référence CVE CVE-2021-21343 https://www.cve.org/CVERecord?id=CVE-2021-21343 Référence CVE CVE-2021-21344 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2020-014442XStream におけるサーバサイドのリクエストフォージェリの脆弱性

XStream には、サーバサイドのリクエストフォージェリの脆弱性が存在します。

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Fixed
Action
For 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 update; after installing the update, restart the server by starting the JBoss Application Server process. The References section of this erratum contains a download link (you must log in to download the update).
Workaround
A mitigation or workaround reference is available from the source linked below; validate it against the affected product and version.
04

Evidence and provenance

Published 16 Dec 2020 · Last source change 7 Oct 2026, 18:41 UTC · CWE-918 · Server-Side Request Forgery (SSRF)

CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2020-1481
Product sourceVendor CSAF · Red Hat Product Security
Remediation sourceVendor CSAF · Red Hat Product Security
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Affected versionsThe structured affected or fixed version information changed.
    Before
    xstream: < 1.4.15 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    xstream: < 1.4.15 · Fixed: For 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 update; after installing the update, restart the server by starting the JBoss Application Server process. The References section of this erratum contains a download link (you must log in to download the update).
    Red Hat Product Security ↗
  2. Remediation statusRemediation status changed from Mitigation available to Patch available.
    Before
    Mitigation available
    After
    Patch available
    Red Hat Product Security ↗
  3. Affected versionsThe structured affected or fixed version information changed.
    Before
    < 1.4.15 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    xstream: < 1.4.15 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Mitigation reference recorded
Fixed release recorded from official guidance
ENISA EUVD · EUVD-2020-1481↗Red Hat Product Security security advisory↗CVE authority or vendor reference · GitHub GHSA-4CCH-WXPW-8P28↗Public exploit reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2020-26258 · cve.blacktree.nl