Cyber Resilience

CVE-2021-20839

Medium

Published: 01 November 2021

Published
01 November 2021
Modified
21 November 2024
KEV Added
—
Patch
—
CVSS Score v3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
EPSS Score 0.0042 62.4th percentile
Risk Priority 13 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-20839 is a medium-severity Improper Restriction of XML External Entity Reference (CWE-611) vulnerability in Antennahouse Office Server Document Converter. Its CVSS base score is 6.5 (Medium).

Operationally, ranked in the top 37.6% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Office Server Document Converter V7.2MR4 and earlier and V7.1MR7 and earlier allows a remote unauthenticated attacker to conduct an XML External Entity (XXE) attack to cause a denial of service (DoS) condition to the other servers by processing a specially…

more

crafted XML document.

CWE(s)
CWE-611

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

antennahouse
office server document converter
5.2, 6.0, 6.1, 7.0, 7.1 · ≤ 5.2

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CA-8 Penetration Testing
addresses: CWE-611

Penetration testing includes XML external entity payloads, detecting XXE vulnerabilities and enabling their mitigation.

SI-4 System Monitoring
addresses: CWE-611

Identifies XML external entity processing via monitoring of unusual file/network access or resource usage.

References