CVE-2021-21342 | A Server-Side Forgery Request can be activated unmarshalling with XStream to access data streams from an arbitrary URL referencing a resource in an intranet or the local host

Exp

XStream is a Java library to serialize objects to XML and back again. In XStream before version 1.4.16, there is a vulnerability where the processed stream at unmarshalling time contains type information to recreate the formerly written objects. XStream creates therefore new instances based on these type information. An attacker can manipulate the processed input stream and replace or inject objects, that result in a server-side forgery request. 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.

Published: 2021-03-22 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-21342 is rated High Exploit Risk (70.6/100): CVSS Medium severity, with high exploitation likelihood (EPSS 49.99%, 99th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2021-21342

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-21342

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-27 50.14% 49.99% -0.15%
2 2026-06-15 0.87% 50.14% +49.28%
3 2026-03-10 — 0.87% —

Full EPSS history (41 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-21342

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 1.6 3.6 [email protected]
9.1 3.1 CRITICAL
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 5.2 [email protected]
5.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 4.9 [email protected]

Weakness enumeration for CVE-2021-21342

GitHub Security Advisory for CVE-2021-21342

GHSA-hvv8-336g-rx3m · Severity: medium · Ecosystem: maven — A Server-Side Forgery Request can be activated unmarshalling with XStream to access data streams from an arbitrary URL referencing a resource in an intranet or the local host

OS Trackers for CVE-2021-21342

vendor priority summary link
debian not yet assigned CVE-2021-21342 not yet assigned priority: Debian including 1 source packages (libxstream-java), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-21342
redhat medium — https://access.redhat.com/security/cve/CVE-2021-21342
suse high CVE-2021-21342 severity important: SUSE including 245 source package names (5.0.0-beta1.2.122:xstream-1.4.16-3.8.1, 5.1.0.6.40:xstream-1.4.16-3.8.1, …), 278 product×package rows across 31 product lines (Container suse/manager/5.0/x86_64/server, Container suse/multi-linux-manager/5.1/x86_64/server, … (31 product lines)): Known Affected 231, Fixed 47. https://www.suse.com/security/cve/CVE-2021-21342/
ubuntu medium CVE-2021-21342 medium priority: Ubuntu including 1 source packages (libxstream-java), 14 status rows across 14 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, trusty, upstream, xenial): released 14. https://ubuntu.com/security/CVE-2021-21342

Affected software / configurations for CVE-2021-21342

Vendor Product Version Raw CPE
netapp oncommand_insight — cpe:2.3:a:netapp:oncommand_insight:-:*:*:*:*:*:*:*
apache activemq < 5.15.14 cpe:2.3:a:apache:activemq:*:*:*:*:*:*:*:*
apache activemq 5.16.0 cpe:2.3:a:apache:activemq:5.16.0:*:*:*:*:*:*:*
apache activemq 5.16.1 cpe:2.3:a:apache:activemq:5.16.1:*:*:*:*:*:*:*
apache jmeter < 5.5 cpe:2.3:a:apache:jmeter:*:*:*:*:*:*:*:*
xstream xstream < 1.4.16 cpe:2.3:a:xstream:xstream:*:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
oracle banking_enterprise_default_management 2.10.0 cpe:2.3:a:oracle:banking_enterprise_default_management:2.10.0:*:*:*:*:*:*:*
oracle banking_enterprise_default_management 2.12.0 cpe:2.3:a:oracle:banking_enterprise_default_management:2.12.0:*:*:*:*:*:*:*
oracle banking_platform 2.4.0 cpe:2.3:a:oracle:banking_platform:2.4.0:*:*:*:*:*:*:*
oracle banking_platform 2.7.1 cpe:2.3:a:oracle:banking_platform:2.7.1:*:*:*:*:*:*:*
oracle banking_platform 2.9.0 cpe:2.3:a:oracle:banking_platform:2.9.0:*:*:*:*:*:*:*
oracle banking_platform 2.12.0 cpe:2.3:a:oracle:banking_platform:2.12.0:*:*:*:*:*:*:*
oracle banking_virtual_account_management 14.2.0 cpe:2.3:a:oracle:banking_virtual_account_management:14.2.0:*:*:*:*:*:*:*
oracle banking_virtual_account_management 14.3.0 cpe:2.3:a:oracle:banking_virtual_account_management:14.3.0:*:*:*:*:*:*:*
oracle banking_virtual_account_management 14.5.0 cpe:2.3:a:oracle:banking_virtual_account_management:14.5.0:*:*:*:*:*:*:*
oracle business_activity_monitoring 11.1.1.9.0 cpe:2.3:a:oracle:business_activity_monitoring:11.1.1.9.0:*:*:*:*:*:*:*
oracle business_activity_monitoring 12.2.1.3.0 cpe:2.3:a:oracle:business_activity_monitoring:12.2.1.3.0:*:*:*:*:*:*:*
oracle business_activity_monitoring 12.2.1.4.0 cpe:2.3:a:oracle:business_activity_monitoring:12.2.1.4.0:*:*:*:*:*:*:*
oracle communications_brm_-_elastic_charging_engine 12.0.0.3 cpe:2.3:a:oracle:communications_brm_-_elastic_charging_engine:12.0.0.3:*:*:*:*:*:*:*
oracle communications_policy_management 12.5.0 cpe:2.3:a:oracle:communications_policy_management:12.5.0:*:*:*:*:*:*:*
oracle communications_unified_inventory_management 7.3.2 cpe:2.3:a:oracle:communications_unified_inventory_management:7.3.2:*:*:*:*:*:*:*
oracle communications_unified_inventory_management 7.3.4 cpe:2.3:a:oracle:communications_unified_inventory_management:7.3.4:*:*:*:*:*:*:*
oracle communications_unified_inventory_management 7.3.5 cpe:2.3:a:oracle:communications_unified_inventory_management:7.3.5:*:*:*:*:*:*:*
oracle communications_unified_inventory_management 7.4.0 cpe:2.3:a:oracle:communications_unified_inventory_management:7.4.0:*:*:*:*:*:*:*
oracle communications_unified_inventory_management 7.4.1 cpe:2.3:a:oracle:communications_unified_inventory_management:7.4.1:*:*:*:*:*:*:*
oracle retail_xstore_point_of_service 16.0.6 cpe:2.3:a:oracle:retail_xstore_point_of_service:16.0.6:*:*:*:*:*:*:*
oracle retail_xstore_point_of_service 17.0.4 cpe:2.3:a:oracle:retail_xstore_point_of_service:17.0.4:*:*:*:*:*:*:*
oracle retail_xstore_point_of_service 18.0.3 cpe:2.3:a:oracle:retail_xstore_point_of_service:18.0.3:*:*:*:*:*:*:*
oracle retail_xstore_point_of_service 19.0.2 cpe:2.3:a:oracle:retail_xstore_point_of_service:19.0.2:*:*:*:*:*:*:*
oracle webcenter_portal 11.1.1.9.0 cpe:2.3:a:oracle:webcenter_portal:11.1.1.9.0:*:*:*:*:*:*:*
oracle webcenter_portal 12.2.1.3.0 cpe:2.3:a:oracle:webcenter_portal:12.2.1.3.0:*:*:*:*:*:*:*
oracle webcenter_portal 12.2.1.4.0 cpe:2.3:a:oracle:webcenter_portal:12.2.1.4.0:*:*:*:*:*:*:*

References for CVE-2021-21342

URL Tags
http://x-stream.github.io/changes.html#1.4.16 Release Notes Third Party Advisory
https://github.com/x-stream/xstream/security/advisories/GHSA-hvv8-336g-rx3m Third Party Advisory
https://lists.apache.org/thread.html/r8244fd0831db894d5e89911ded9c72196d395a90ae655414d23ed0dd%40%3Cusers.activemq.apache.org%3E Issue Tracking Mailing List Third Party Advisory
https://lists.apache.org/thread.html/r9ac71b047767205aa22e3a08cb33f3e0586de6b2fac48b425c6e16b0%40%3Cdev.jmeter.apache.org%3E Issue Tracking Mailing List Third Party Advisory
https://lists.debian.org/debian-lts-announce/2021/04/msg00002.html Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/22KVR6B5IZP3BGQ3HPWIO2FWWCKT3DHP/ Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/PVPHZA7VW2RRSDCOIPP2W6O5ND254TU7/ Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QGXIU3YDPG6OGTDHMBLAFN7BPBERXREB/ Mailing List Third Party Advisory
https://security.netapp.com/advisory/ntap-20210430-0002/ Third Party Advisory
https://www.debian.org/security/2021/dsa-5004 Mailing List Third Party Advisory
https://www.oracle.com//security-alerts/cpujul2021.html Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.html Not Applicable Patch Vendor Advisory
https://www.oracle.com/security-alerts/cpuoct2021.html Third Party Advisory
https://x-stream.github.io/CVE-2021-21342.html Exploit Third Party Advisory
https://x-stream.github.io/security.html#workaround Mitigation Third Party Advisory
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