Cyber Resilience

CVE-2021-43449

HighPublic PoC

Published: 23 January 2023

Published
23 January 2023
Modified
02 April 2025
KEV Added
—
Patch
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CVSS Score v3.1 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N
EPSS Score 0.0075 73.6th percentile
Risk Priority 17 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-43449 is a high-severity SSRF (CWE-918) vulnerability in Onlyoffice Server. Its CVSS base score is 8.1 (High).

Operationally, ranked in the top 26.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

ONLYOFFICE all versions as of 2021-11-08 is vulnerable to Server-Side Request Forgery (SSRF). The document editor service can be abused to read and serve arbitrary URLs as a document.

CWE(s)
CWE-918

Related Threats

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

Affected Assets

onlyoffice
server
≤ 7.0.0.49

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-918

Penetration testing attempts server-side requests to internal resources, identifying SSRF weaknesses for remediation.

SC-7 Boundary Protection
addresses: CWE-918

Outbound connections to external resources can be monitored and limited at the boundary, reducing SSRF impact.

SI-10 Information Input Validation
addresses: CWE-918

Validates server-side URLs and resource references to block SSRF attempts.

SI-4 System Monitoring
addresses: CWE-918

Detects server-side request forgery through monitoring of unexpected outbound connections.

References