CVE-2021-20839

Name: CVE-2021-20839
Creator: NVD / NIST
Published: 2021-11-01T02:15:06.923+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.5/10EPSS 1.10%

Last modified Jun 17, 2026

CVE-2021-20839 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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 crafted XML document.. EPSS estimates a 1.10% chance of exploitation in the next 30 days.

Description

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 crafted XML document.

Metrics

CVSS 3.1

6.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H

EPSS Probability

1.10%

61.5th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-611

Affected Software

Vendor	Product	Versions
Antennahouse	Office Server Document Converter	< 5.2
Antennahouse	Office Server Document Converter	5.2
Antennahouse	Office Server Document Converter	6.0
Antennahouse	Office Server Document Converter	6.1
Antennahouse	Office Server Document Converter	7.0
Antennahouse	Office Server Document Converter	7.1
Antennahouse	Office Server Document Converter	7.2

References

https://jvn.jp/en/jp/JVN33453839/index.htmlThird Party Advisory
https://www.antenna.co.jp/news/2021/osdc72-20211027.htmlPatch, Vendor Advisory
https://jvn.jp/en/jp/JVN33453839/index.htmlThird Party Advisory
https://www.antenna.co.jp/news/2021/osdc72-20211027.htmlPatch, Vendor Advisory

Timeline

Published: Nov 1, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-20839?

How severe is CVE-2021-20839?

CVE-2021-20839 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 1.10% probability of exploitation in the next 30 days.

How do I fix CVE-2021-20839?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-20839?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST