CVE-2021-39144

CVE-2021-39144 is a high-severity vulnerability in Xstream with a CVSS 3.x base score of 8.5. It is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, confirming it has been exploited in the wild (added 2023-03-10). The underlying weakness is classified as CWE-306.

Key facts

Description

XStream is a simple library to serialize objects to XML and back again. In affected versions this 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. XStream 1.4.18 uses no longer a blacklist by default, since it cannot be secured for general purpose.

Frequently asked questions

What is CVE-2021-39144?
XStream is a simple library to serialize objects to XML and back again. In affected versions this 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. XStream 1.4.18 uses no longer a blacklist by default, since it cannot be secured for general purpose.
How severe is CVE-2021-39144?
CVE-2021-39144 has a CVSS 3.x base score of 8.5, rated high severity. It is exploitable over network with high attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-39144 being actively exploited?
Yes. CVE-2021-39144 is on CISA's Known Exploited Vulnerabilities (KEV) catalog, added on 2023-03-10, which means active exploitation has been confirmed. It should be prioritised for remediation.
What products are affected by CVE-2021-39144?
CVE-2021-39144 primarily affects Xstream. In total, 36 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-39144?
Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Because this CVE is known to be actively exploited, treat remediation as urgent — CISA KEV typically sets a short remediation deadline.
Does CVE-2021-39144 have an EU (EUVD) identifier?
Yes. CVE-2021-39144 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2021-1771. It is also flagged as exploited in the EUVD (since 2023-03-10).
When was CVE-2021-39144 published?
CVE-2021-39144 was published on 2021-08-23 and last updated on 2026-06-17.

References

Affected products (36)

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