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ServerApplication · Onlyoffice

CVE-2021-43444

HIGH · 7.5 CVSS v3.1 Published 2023-01-23
Fix available
A fix is available. Upgrade to after 7.0.0.49 or later.
See remediation →
84/100
Remediation priority · High
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
ONLYOFFICE all versions as of 2021-11-08 is affected by Incorrect Access Control. Signed document download URLs can be forged due to a weak default URL signing key.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

ONLYOFFICE all versions as of 2021-11-08 contain an incorrect access control vulnerability where signed document download URLs can be forged due to a weak default URL signing key. An attacker who discovers or guesses the weak key could generate valid download URLs for documents they do not have authorized access to, bypassing authentication controls.

MitigationReplace the weak default URL signing key with a cryptographically strong, randomly generated key and implement proper key management procedures including rotation.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
ServerApplication
Affected:<= 7.0.0.49

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify the installed Onlyoffice Server version
    Locate the installed version of Onlyoffice Server. This is typically visible in the server administration panel, about page, or installation logs. Compare your installed version against the affected range: versions 7.0.0.49 and earlier.
    Affected if The installed version is 7.0.0.49 or lower
  2. Determine if document URL signing is active
    Check the Onlyoffice Server configuration to see if signed download URLs for documents are enabled or used. Look for settings related to document sharing, URL generation, or download link security.
    Affected if URL signing for document downloads is enabled and the server version is within the affected range
  3. Inspect the URL signing key configuration
    Examine the Onlyoffice configuration files or settings for the URL signing key. Look for parameters controlling document download URL validation or token generation.
    Affected if A default, unchanged, or weak URL signing key is configured, or no custom key has been explicitly set

The environment is affected if the installed Onlyoffice Server version is 7.0.0.49 or earlier AND document download URL signing uses a default or weak key.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 7.0.0.49
Interim mitigation

Replace the weak default URL signing key with a cryptographically strong, randomly generated key and implement proper key management procedures including rotation.

Recommended fix Moderate confidence

Upgrade to the latest stable ONLYOFFICE Server release (version 7.0.1 or later as indicated in official security advisories)

  1. 1. Identify the current ONLYOFFICE Server version installed by checking the About section in the control panel or running the diagnostic command provided in your deployment documentation.
  2. 2. Check the official ONLYOFFICE release notes at www.onlyoffice.com for security updates after version 7.0.0.49.
  3. 3. If an updated package is available, download it from the official ONLYOFFICE repository (github.com) or your distribution's package manager.
  4. 4. Before upgrading, backup the entire ONLYOFFICE data directory and database to ensure rollback capability.
  5. 5. Apply the upgrade following the official upgrade instructions specific to your deployment method (Docker, Linux package, or Windows installer).
  6. 6. After upgrade, verify the server starts successfully and document download URLs are now properly signed with the new key mechanism.
  7. 7. Additionally, if you have not already done so, change any default URL signing keys to strong, unique values in the configuration file (typically communityserver.conf or similar).
Caveat Review release notes for potential breaking changes between 7.0.0.x and newer versions, particularly regarding document storage and authentication plugins

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Server Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA2.0 h
20.0 hours of engineering $3,500
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-43444 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data