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PatchSiren cyber security CVE debrief

CVE-2021-39144 XStream CVE debrief

CVE-2021-39144 is a remote code execution vulnerability affecting XStream that CISA added to the Known Exploited Vulnerabilities catalog on 2023-03-10. Because it is listed in KEV, organizations should treat it as a high-priority remediation item and follow the vendor’s update guidance promptly.

Vendor
XStream
Product
XStream
CVSS
HIGH 8.5
CISA KEV
Listed
Original CVE published
2023-03-10
Original CVE updated
2023-03-10
Advisory published
2023-03-10
Advisory updated
2023-03-10

Who should care

Any organization that uses XStream in production, development, or embedded software should prioritize this issue, especially teams responsible for application security, platform engineering, and vulnerability management.

Technical summary

The available official records identify this issue as a remote code execution vulnerability in XStream. CISA’s KEV entry indicates it is known to be exploited in the wild and directs defenders to apply updates per vendor instructions. The supplied source corpus does not provide additional technical details about the trigger, affected versions, or exploit path.

Defensive priority

High. KEV inclusion means this vulnerability is already known to be exploited, so remediation should be prioritized ahead of routine patch cycles and completed as soon as vendor guidance can be applied.

Recommended defensive actions

  • Inventory all systems, applications, and libraries that use XStream.
  • Apply the vendor-recommended updates or mitigations as soon as possible.
  • Track remediation against the CISA KEV due date of 2023-03-31.
  • Validate that patched versions are deployed across development, test, and production environments.
  • Retest affected applications after updating to confirm they still function as expected.

Evidence notes

This debrief is based on the supplied CISA KEV source item and official references to the CVE record, NVD, and the vendor advisory link provided in the source metadata. The source corpus confirms the vulnerability name, KEV status, date added, due date, and the instruction to apply updates per vendor guidance. No CVSS score or affected-version details were supplied.

Sources and references

Verified primary and authoritative sources

  • CVE-2021-39144 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2021-39144

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2021-39144 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2021-39144

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

  • CISA Known Exploited Vulnerabilities catalog

    Publisher, destination, and source semantics verified

    URL: https://www.cisa.gov/known-exploited-vulnerabilities-catalog

    Cybersecurity and Infrastructure Security Agency - Official CISA catalog of vulnerabilities known to be exploited in the wild.

Supplemental references

  • Source item URL

    Unverified legacy reference

    URL: https://www.cisa.gov/sites/default/files/feeds/known_exploited_vulnerabilities.json

    cisa_kev

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.