VulnTideExploited vulnerabilities, by vendor. Data as of .
Not in CISA KEVReported exploited: VulnCheck KEV since Published CVSS 8.5 highEPSS 11.4% probability of exploitation in 30 days
XStream

CVE-2021-39152: A Server-Side Forgery Request vulnerability in XStream via HashMap unmarshaling

Is it exploited?

Reported, not confirmed by CISA. VulnCheck KEV lists it as exploited in the wild. CISA has not added it to its Known Exploited Vulnerabilities catalog as of .

VulnCheck KEV lists it since . It cites 1 public report, the first from .

How likely is exploitation in the next 30 days?
11.4%

EPSS score, percentile 96 of all scored records. A probability estimated by FIRST, not a report of exploitation.

How severe?
8.5 High

CVSS v3.1 base score, given by the CNA

What should I do?

CISA has set no required action, because the vulnerability is not in KEV.

Advisories and patches (4)

Which versions are affected?

Affected

  • < 1.4.18

Versions by product

Source: CISA KEV 2026.10.29, as of ; VulnCheck KEV, as of ; FIRST EPSS, as of ; CVE List, as of . About the data.

Description

A Server-Side Forgery Request vulnerability in XStream via HashMap unmarshaling

XStream is a simple library to serialize objects to XML and back again. In affected versions this vulnerability may allow a remote attacker to request data from internal resources that are not publicly available only by manipulating the processed input stream with a Java runtime version 14 to 8. 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](https://x-stream.github.io/security.html#framework), you will have to use at least version 1.4.18.

Source: CVE List, as of . About the data.

What to do

Advisories and patches

This summary is based on the CVE record as of . Check the vendor's advisory before you act: affected versions and fixes can change.

Affected products and versions

Versions by product, as listed in the CVE record (1 product)
x-stream xstream
StatusVersions
Affected< 1.4.18

Source: CVE List, as of . About the data.

Weakness

CWE-502, CWE-918
  • CWE-502: Deserialization of Untrusted Data
  • CWE-918: Server-Side Request Forgery (SSRF)

CWE and CAPEC are maintained by MITRE; the entries are those named in the CVE record.

Timeline

DateEvent
CVE record published
CVE record last updated

References

7

Known exploited XStream vulnerabilities

  • CVE-2021-39144: XStream Remote Code Execution Vulnerability (added )