CVE-2021-20839: Office Server Document Converter V7.2MR4 and earlier and V7.1MR7 and earlier allows a remote unauthenticated a

Q: How do I fix CVE-2021-20839?

office server document converter: upgrade to 5.2. Exact commands for each OS are on this page.

Q: Is CVE-2021-20839 being exploited?

CVE-2021-20839 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2021-20839 affect?

CVE-2021-20839 affects office server document converter. Severity is medium (CVSS 6.5). 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 proces

Q: How urgent is CVE-2021-20839?

Priority 39/100. No elevated risk signals yet.

Routine

MEDIUM 6.5UPGRADE

CVE-2021-20839 is a medium-severity flaw (CVSS 6.5) affecting office server document converter. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	1.1% (top 33%)
CISA exploited list	No
Weakness	CWE-611
Published	2021-11-01
Last modified	2026-06-17

Publisher (CNA): JPCERT/CC · Vendor: antennahouse

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2021-11-01 02:15 UTCPublished CVE record published
2026-06-17 03:34 UTCUpdated Record last modified

antennahouse office server document converter UPGRADE

Affected: < 5.2 · 5.2 · 6.0 · 6.0 mr1 · 6.0 mr2 · 6.1 · 6.1 mr2 · 6.1 mr3

Fixed in: 5.2

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy office-server-document-converter || rpm -q office-server-document-converter || office-server-document-converter --version

2. UPGRADE to 5.2 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade office-server-document-converter

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade office-server-document-converter

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2021-20839?

office server document converter: upgrade to 5.2. Exact commands for each OS are on this page.

Is CVE-2021-20839 being exploited?

CVE-2021-20839 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2021-20839 affect?

CVE-2021-20839 affects office server document converter. Severity is medium (CVSS 6.5). 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 proces

How urgent is CVE-2021-20839?

Priority 39/100. No elevated risk signals yet.

Related CVEs

CVE-2021-20838 HIGH 7.5 UPGRADE Office Server Document Converter V7.2MR4 and earlier and V7.1MR7 and earlier allows a remote unauthenticated a

References

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