CVE-2021-21345

mediumpriority · attend · 75EPSS 0.723 · 99 %ileexploit · PoCDEEURUUS
grimoire priorityP1 · Urgent
Exploitable?
Public exploit
1 exploit · PoC
Likely / severe?
72.3% (99th) EPSS
CVSS 6.5 · medium
Is it mine?
116 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · fstec_bdu · osv

EPSS · scored 2026-10-27

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability which may allow a remote attacker who has sufficient rights to execute commands of the host 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.

01

cvss

Technical severity, 0–10. One row per scoring source.

9.9
010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–critical · 5.8–9.9

v2.06.5mediumAV:N/AC:L/Au:S/C:P/I:P/A:Pprimary · NVD / NIST USexploitability 8 · impact 6.4
v3.19.9criticalCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 3.1 · impact 6
v3.19.9criticalAV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:Hsecondary · FSTEC (BDU) RU
v3.15.8mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:H/A:Nsecondary · ENISA EU
v3.15.8mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:H/A:Nsecondary · security-advisories@github.comexploitability 1.3 · impact 4
v3.15.8mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:N/I:H/A:Nsecondary · OSV
v3.19.9criticalCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:Hsecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

04

exploits (1)

Public proof-of-concept and weaponised exploit code.

05

affected products (116)

Products and version ranges known to be affected.

06

advisories (4)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2024-1689Dell Data Protection Advisor: Mehrere Schwachstellen ermöglichen CodeausführungDeutsch2024-07-22csaf · cert_bundDE

    Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Dell Data Protection Advisor ausnutzen, um beliebigen Programmcode auszuführen.

  • WID-SEC-W-2026-0180Dell Data Protection Advisor: Mehrere SchwachstellenDeutsch2026-01-20csaf · cert_bundDE

    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.

  • GHSA-hwpc-8xqv-jvj4XStream is vulnerable to a Remote Command Execution attack2021-03-22ghsa · osvUS

    ### Impact The vulnerability may allow a remote attacker has sufficient rights to execute commands of the host 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. ### Patches If you rely on XStream's default blacklist of the [Security Framework](https://x-stream.github.io/security.html#framework), you will have to use at least version 1.4.16. ### Workarounds See [workarounds](https://x-stream.github.io/security.html#workaround) for the different versions covering all CVEs. ### References See full information about the nature of the vulnerability and the steps to reproduce it in XStream's documentation for [CVE-2021-21345](https://x-stream.github.io/CVE-2021-21345.html). ### Credits 钟潦贵 (Liaogui Zhong) found and reported the issue to XStream and provided the required information to reproduce it. ### For more information If you have any questions or comments about this advisory: * Open an issue in [XStream](https://github.com/x-stream/xstream/issues) * Contact us at [XStream Google Group](https://groups.google.com/group/xstream-user)

  • BIT-activemq-2021-21345XStream is vulnerable to a Remote Command Execution attack2025-12-03vendor · osvUS

    XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability which may allow a remote attacker who has sufficient rights to execute commands of the host 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.

07

also known as (6)

Other names and identifiers for this entity.

08

sources

Which sources assert this record, and when.

10

references (78)

External citations — patches, advisories, analysis.

scry

Attackers weaponise vulnerabilities like this against internet-exposed services. See what is exposed on your perimeter with a free passive scan.

Free scan