BlackTreeCVE Intelligence
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Full vulnerability report · 2021
CVE-2021-21341High confidence

XStream can cause a Denial of Service

x-stream · xstream

7.5HighCVSS 3.1
Recommended action
Within 7 days

High 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 severityHighOperational priority:Critical, raised one band.upgradedsince 3 Aug 2024

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • A structured source references public exploit or proof-of-concept material.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 77.80% 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 3 daysRemediation target: Within 90 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.1.4.15-2Debian Security Tracker ↗Source updated 7 Oct 2026
Debian bookwormbookworm · sourcelibxstream-javaVendor fix publishedDebian records a fixed source-package version for this release.1.4.15-2Debian Security Tracker ↗Source updated 7 Oct 2026
Debian forkyforky · sourcelibxstream-javaVendor fix publishedDebian records a fixed source-package version for this release.1.4.15-2Debian Security Tracker ↗Source updated 7 Oct 2026
Debian sidsid · sourcelibxstream-javaVendor fix publishedDebian records a fixed source-package version for this release.1.4.15-2Debian Security Tracker ↗Source updated 7 Oct 2026
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-2021-0586

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

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
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionWithin 7 days

High 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 1.4.16, there is vulnerability which may allow a remote attacker to allocate 100% CPU time on the target system depending on CPU type or parallel execution of such a payload resulting in a denial of service only by manipulating the processed input stream. No user is affected who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.16.

What

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is vulnerability which may allow a remote attacker to allocate 100% CPU time on the target system depending on CPU type or parallel execution of such a payload resulting in a denial of service only by manipulating the processed input stream. No user is affected who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.16.

Why

The product does not properly control the allocation and maintenance of a limited resource.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is vulnerability which may allow a remote attacker to allocate 100% CPU time on the target system depending on CPU type or parallel execution of such a payload resulting in a denial of service only by manipulating the processed input stream. No user is affected who followed the recommendation to setup XStream's security framework with a whitelist limited to the minimal required types. If you rely on XStream's default blacklist of the Security Framework, you will have to use at least version 1.4.16.

Why

The product does not properly control the allocation and maintenance of a limited resource.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

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 → Uncontrolled Resource Consumption → disrupt the affected service
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-400 ↗

CWE-400: Uncontrolled Resource Consumption. The product does not properly control the allocation and maintenance of a limited resource.

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:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
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.
NetworkUnauthenticatedDenial of serviceCWE-400Public exploit reference
A

Official authority intelligence

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

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-20210324Security Bulletin 24 Mar 2021

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 24 Mar 2021, published on 24 March 2021. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-951Multiples vulnérabilités dans le noyau Linux de RedHat

ERecord?id=CVE-2020-27782 Référence CVE CVE-2020-28491 https://www.cve.org/CVERecord?id=CVE-2020-28491 Référence CVE CVE-2020-2875 https://www.cve.org/CVERecord?id=CVE-2020-2875 Référence CVE CVE-2020-2934 https://www.cve.org/CVERecord?id=CVE-2020-2934 Référence CVE CVE-2020-35510 https://www.cve.org/CVERecord?id=CVE-2020-35510 Référence CVE CVE-2020-9488 https://www.cve.org/CVERecord?id=CVE-2020-9488 Référence CVE CVE-2021-20218 https://www.cve.org/CVERecord?id=CVE-2021-20218 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=CVE-2021-21344 Référence CVE CVE-2021-21345 https://www.cve.org/CVERecord?id=CVE-2021-21345 Référence CVE CVE-2021-21346 https://www.cve.org/CVERecord?id=CVE-2021-21346 Référence CVE CVE-2021-21347 https://www.cve.org/CVERecord?id=CVE-2021-21347 Référence CVE CVE-2021-21348 https://www.cve.org/CVERecord?id=CVE-2021-21348 Référence CVE CVE-2021-21349 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-948Multiples vulnérabilités dans les produits SAP

BDISP 7.53, 7.73, 7.77, 7.81, 7.82, 7.83, KERNEL 7.21, 7.22, 7.49, 7.53, 7.73, 7.77, 7.81, 7.82, 7.83 Résumé De multiples vulnérabilités ont été découvertes dans les produits SAP. Elles permettent à un attaquant de provoquer une exécution de code arbitraire à distance et un déni de service à distance. Solution Se référer au bulletin de sécurité de l'éditeur pour l'obtention des correctifs (cf. section Documentation). Documentation Bulletin de sécurité SAP du 14 décembre 2021 https://wiki.scn.sap.com/wiki/display/PSR/SAP+Security+Patch+Day+-+December+2021 Référence CVE CVE-2019-0388 https://www.cve.org/CVERecord?id=CVE-2019-0388 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=CVE-2021-21344 Référence CVE CVE-2021-21345 https://www.cve.org/CVERecord?id=CVE-2021-21345 Référence CVE CVE-2021-21346 https://www.cve.org/CVERecord?id=CVE-2021-21346 Référence CVE CVE-2021-21347 https://www.cve.org/CVERecord?id=CVE-2021-21347 Référence CVE CVE-2021-21348 https://www.cve.org/CVERecord?id=CVE-2021-21348 Référence CVE CVE-2021-21349 https://www.cve.org/CVERecord?id=

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

ord?id=CVE-2020-36183 Référence CVE CVE-2020-36184 https://www.cve.org/CVERecord?id=CVE-2020-36184 Référence CVE CVE-2020-36185 https://www.cve.org/CVERecord?id=CVE-2020-36185 Référence CVE CVE-2020-36186 https://www.cve.org/CVERecord?id=CVE-2020-36186 Référence CVE CVE-2020-36187 https://www.cve.org/CVERecord?id=CVE-2020-36187 Référence CVE CVE-2020-36188 https://www.cve.org/CVERecord?id=CVE-2020-36188 Référence CVE CVE-2020-36189 https://www.cve.org/CVERecord?id=CVE-2020-36189 Référence CVE CVE-2020-7656 https://www.cve.org/CVERecord?id=CVE-2020-7656 Référence CVE CVE-2021-20190 https://www.cve.org/CVERecord?id=CVE-2021-20190 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=CVE-2021-21344 Référence CVE CVE-2021-21345 https://www.cve.org/CVERecord?id=CVE-2021-21345 Référence CVE CVE-2021-21346 https://www.cve.org/CVERecord?id=CVE-2021-21346 Référence CVE CVE-2021-21347 https://www.cve.org/CVERecord?id=CVE-2021-21347 Référence CVE CVE-2021-21348 https://www.cve.org/CVERecord?id=CVE-2021-21348 Référence CVE CVE-2021-21349 https://www.cve.org/CVERecord?id=

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

rt/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=CVE-2021-21343 Référence CVE CVE-2021-21344 https://www.cve.org/CVERecord?id=CVE-2021-21344 Référence CVE CVE-2021-21345 https://www.cve.org/CVERecord?id=CVE-2021-21345 Référence CVE CVE-2021-21346 https://www.cve.org/CVERecord?id=CVE-2021-21346 Référence CVE CVE-2021-21347 https://www.cve.org/CVERecord?id=CVE-2021-21347 Référence CVE CVE-2021-21348 https://www.cve.org/CVERecord?id=CVE-2021-21348 Référence CVE CVE-2021-21349 https://www.cve.org/CVERecord?id=

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

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=CVE-2021-21344 Référence CVE CVE-2021-21345 https://www.cve.org/CVERecord?id=CVE-2021-21345 Référence CVE CVE-2021-21346 https://www.cve.org/CVERecord?id=CVE-2021-21346 Référence CVE CVE-2021-21347 https://www.cve.org/CVERecord?id=CVE-2021-21347 Référence CVE CVE-2021-21348 https://www.cve.org/CVERecord?id=CVE-2021-21348 Référence CVE CVE-2021-21349 https://www.cve.org/CVERecord?id=

Official advisory ↗
CERT-FR · French · CERTFR-2021-AVI-395Multiples vulnérabilités dans IBM Spectrum Control

e code arbitraire à distance, un déni de 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 6454803 du 20 mai 2021 https://www.ibm.com/support/pages/node/6454803 Référence CVE CVE-2020-14781 https://www.cve.org/CVERecord?id=CVE-2020-14781 Référence CVE CVE-2020-14782 https://www.cve.org/CVERecord?id=CVE-2020-14782 Référence CVE CVE-2020-27221 https://www.cve.org/CVERecord?id=CVE-2020-27221 Référence CVE CVE-2020-5258 https://www.cve.org/CVERecord?id=CVE-2020-5258 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=CVE-2021-21344 Référence CVE CVE-2021-21345 https://www.cve.org/CVERecord?id=CVE-2021-21345 Référence CVE CVE-2021-21346 https://www.cve.org/CVERecord?id=CVE-2021-21346 Référence CVE CVE-2021-21347 https://www.cve.org/CVERecord?id=CVE-2021-21347 Référence CVE CVE-2021-21348 https://www.cve.org/CVERecord?id=CVE-2021-21348 Référence CVE CVE-2021-21349 https://www.cve.org/CVERecord?id=

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2021-004707XStream におけるリソースの枯渇に関する脆弱性

XStream には、リソースの枯渇に関する脆弱性、および信頼できないデータのデシリアライゼーションに関する脆弱性が存在します。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-5471SAP 제품 취약점 보안 업데이트 권고

#### SAP 제품 취약점 보안 업데이트 권고 2021.12.16 ##### □ 개요 o SAP 社는 자사 제품의 취약점을 해결한 보안 업데이트 공지 [1] o 공격자는 취약점을 악용하여 피해를 발생시킬 수 있으므로, 해당 제품을 사용하는 이용자들은 최신 버전으로 업데이트 권고 ##### □ 설명 [1] o SAP Commerce에서 발생하는 코드실행 취약점(CVE-2021-21341) 등 11개 o SAP ABAP Server 및 ABAP Platform에서 발생하는 코드 삽입 취약점(CVE-2021-44231) o SAP NZDT에서 발생하는 SQL 인젝션 취약점(CVE-2021-38176) o SAP Commerce에서 발생하는 SQL 인젝션 취약점(CVE-2021-42064) o SAP Knowledge Warehouse에서 발생하는 XSS 취약점(CVE-2021-42063) o SAP NetWeaver AS ABAP에서 발생하는 코드 삽입 취약점(CVE-2021-44235) o SAP SuccessFactors Mobile Application에서 발생하는 서비스거부 취약점(CVE-2021-40498) o SAF-T Framework에서 발생하는 경로 탐색 취약점(CVE-2021-44232) o SAP Commerce에서 발생하는 서비스거부 취약점(CVE-2021-37714) ##### □ 영향받는 제품 o SAP Commerce : 1905, 2001, 2005, 2105, 2011 o SAP ABAP Server & ABAP Platform : 701, 740, 750, 751, 752, 753, 754, 755, 756, 804 o SAP NZDT Mapping Talbe Framework - SAP S/4HA

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
xstream: < 1.4.16
Fixed
An authoritative update reference is available, but the fixed version is not recorded in the structured CVE fields. Check the linked vendor advisory for the applicable release.
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
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 22 Mar 2021 · Last source change 3 Aug 2024, 18:09 UTC · CWE-400 · Uncontrolled Resource Consumption

CVE recordCVE.org · 5.1
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-2021-0586
Product sourceCNA
Remediation sourceCVE/CNA references
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 ↗

No material field changes have been recorded since change tracking began. Routine source refreshes and cosmetic edits are intentionally excluded.

Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
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-2021-21341 · cve.blacktree.nl