SARA / Free Tools / CVE / CVE-2021-39144

CVE-2021-39144 — XStream Remote Code Execution Vulnerability

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

CVSS
8.5 HIGH
EPSS
94.25% (top 0.10%)
CWE
CWE-94, CWE-502
Published
2021-08-23T00:00:00.000Z
Last modified
2025-10-21T23:25:37.489Z
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CISA KEV — Actively Exploited
Added to KEV
2023-03-10
BOD 22-01 due
2023-03-31
Ransomware use
Unknown

01What is this vulnerability?

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…

02Affected products

VendorProductVersions
x-streamxstream< 1.4.18

03Active exploitation status

Yes — actively exploited. Added to the CISA KEV catalog on 2023-03-10. Ransomware use: Unknown.

04Recommended remediation

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Open the Sigma generator with a pre-filled prompt for this CVE to draft a starting detection in your stack of choice:

Open in Sigma generator →

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

09References

Want this in your SOAR or SIEM?
SARA's API returns EPSS, CVSS, KEV, and an analyst-grade summary in one call.
Read the API reference →