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CVE-2021-21343

Is CVE-2021-21343 real, exploitable, or a false positive? Here's the community verdict.

Community verdict: No field verdicts yet. Be the first practitioner to weigh in.

signals

public sources

Exploited in wild
Not listed
CISA KEV
Public exploit
None known
Metasploit/EDB/PoC
Base severity
5.3 Medium
CVSS
Exploitation prob.
47%
FIRST EPSS
Weakness
CWE-73
CWE

Moderate signals. Triage by your actual exposure and reachability.

baseline read

auto · not a community verdict

Low signal — verdict needed

Few public signals point to active risk. Whether a scanner hit here is a true or false positive depends on your version and config — community verdicts decide.

Based on CVSS · FIRST EPSS

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CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:N/I:H/A:N

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 the deletion of a file on the local host. 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.

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    Same weakness: CWE-73.