CVE-2021-20839

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.

Published: 2021-11-01 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-20839 is rated Moderate Risk (48.1/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.10%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-20839

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.42% 1.10% +0.68%
2 2025-03-17 0.18% 0.42% +0.24%
3 2023-03-07 — 0.18% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-20839

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2021-20839

Affected software / configurations for CVE-2021-20839

Vendor Product Version Raw CPE
antennahouse office_server_document_converter < 5.2 cpe:2.3:a:antennahouse:office_server_document_converter:*:*:*:*:*:*:*:*
antennahouse office_server_document_converter 5.2 cpe:2.3:a:antennahouse:office_server_document_converter:5.2:-:*:*:*:*:*:*
antennahouse office_server_document_converter 6.0 cpe:2.3:a:antennahouse:office_server_document_converter:6.0:-:*:*:*:*:*:*
antennahouse office_server_document_converter 6.0 cpe:2.3:a:antennahouse:office_server_document_converter:6.0:mr1:*:*:*:*:*:*
antennahouse office_server_document_converter 6.0 cpe:2.3:a:antennahouse:office_server_document_converter:6.0:mr2:*:*:*:*:*:*
antennahouse office_server_document_converter 6.1 cpe:2.3:a:antennahouse:office_server_document_converter:6.1:-:*:*:*:*:*:*
antennahouse office_server_document_converter 6.1 cpe:2.3:a:antennahouse:office_server_document_converter:6.1:mr2:*:*:*:*:*:*
antennahouse office_server_document_converter 6.1 cpe:2.3:a:antennahouse:office_server_document_converter:6.1:mr2:*:*:pro:*:*:*
antennahouse office_server_document_converter 6.1 cpe:2.3:a:antennahouse:office_server_document_converter:6.1:mr3:*:*:*:*:*:*
antennahouse office_server_document_converter 6.1 cpe:2.3:a:antennahouse:office_server_document_converter:6.1:mr4:*:*:*:*:*:*
antennahouse office_server_document_converter 7.0 cpe:2.3:a:antennahouse:office_server_document_converter:7.0:*:*:*:*:*:*:*
antennahouse office_server_document_converter 7.0 cpe:2.3:a:antennahouse:office_server_document_converter:7.0:mr1:*:*:*:*:*:*
antennahouse office_server_document_converter 7.0 cpe:2.3:a:antennahouse:office_server_document_converter:7.0:mr2:*:*:*:*:*:*
antennahouse office_server_document_converter 7.0 cpe:2.3:a:antennahouse:office_server_document_converter:7.0:mr3:*:*:*:*:*:*
antennahouse office_server_document_converter 7.1 cpe:2.3:a:antennahouse:office_server_document_converter:7.1:-:*:*:*:*:*:*
antennahouse office_server_document_converter 7.1 cpe:2.3:a:antennahouse:office_server_document_converter:7.1:mr1:*:*:*:*:*:*
antennahouse office_server_document_converter 7.1 cpe:2.3:a:antennahouse:office_server_document_converter:7.1:mr2:*:*:*:*:*:*
antennahouse office_server_document_converter 7.1 cpe:2.3:a:antennahouse:office_server_document_converter:7.1:mr3:*:*:*:*:*:*
antennahouse office_server_document_converter 7.2 cpe:2.3:a:antennahouse:office_server_document_converter:7.2:*:*:*:*:*:*:*
antennahouse office_server_document_converter 7.2 cpe:2.3:a:antennahouse:office_server_document_converter:7.2:mr1:*:*:*:*:*:*
antennahouse office_server_document_converter 7.2 cpe:2.3:a:antennahouse:office_server_document_converter:7.2:mr2:*:*:*:*:*:*
antennahouse office_server_document_converter 7.2 cpe:2.3:a:antennahouse:office_server_document_converter:7.2:mr3:*:*:*:*:*:*
antennahouse office_server_document_converter 7.2 cpe:2.3:a:antennahouse:office_server_document_converter:7.2:mr4:*:*:*:*:*:*

References for CVE-2021-20839

cvelogic Threat Intelligence