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OpenofficeApplication · Apache

CVE-2021-40439

MEDIUM · 6.5 CVSS v3.1 Published 2021-10-07
Fix available
A fix is available. Upgrade to after 4.1.10 or later.
See remediation →
72/100
Remediation priority · Elevated
Remotely reachable No privileges

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
Apache OpenOffice has a dependency on expat software. Versions prior to 2.1.0 were subject to CVE-2013-0340 a "Billion Laughs" entity expansion denial of service attack and exploit via crafted XML files. ODF files consist of a set of XML files. All versions of Apache OpenOffice up to 4.1.10 are subject to this issue. expat in version 4.1.11 is patched.

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 · high confidence

Apache OpenOffice uses the expat XML parsing library, which versions prior to 2.1.0 are vulnerable to CVE-2013-0340, the 'Billion Laughs' entity expansion denial-of-service attack. Since ODF files are XML-based, opening a crafted malicious ODF document can trigger infinite loop or memory exhaustion in the vulnerable expat version.

MitigationUpdate the expat library dependency to version 2.1.0 or later in the OpenOffice build, which contains the fix for the entity expansion DoS vulnerability.

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
OpenofficeApplication
Affected:<= 4.1.10

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
Required
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

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

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. Confirm Apache OpenOffice installation
    Check if OpenOffice is installed on the system by searching for the application in standard installation directories or using system package managers
    Affected if OpenOffice is not installed on the system - not applicable
  2. Identify installed OpenOffice version
    Run the OpenOffice executable with version information flags, or check the application's properties/metadata file
    Affected if Version is 4.1.10 or lower - vulnerable
  3. Locate the expat XML library bundled with OpenOffice
    Search for expat library files (libexpat on Linux, expat.dll on Windows) within the OpenOffice installation directory structure
    Affected if The expat library file cannot be located in the OpenOffice installation
  4. Determine expat library version
    Examine the expat library file version using operating system tools or file information utilities
    Affected if The expat version is earlier than 2.1.0 - vulnerable

A user is affected if they have OpenOffice version 4.1.10 or lower with an expat library version prior to 2.1.0 bundled in the OpenOffice installation

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 4.1.10
Interim mitigation

Update the expat library dependency to version 2.1.0 or later in the OpenOffice build, which contains the fix for the entity expansion DoS vulnerability.

Recommended fix Moderate confidence

Apache OpenOffice 4.1.11 or later

  1. 1. Check the current installed version of Apache OpenOffice by opening the application and navigating to Help > About Apache OpenOffice, or by running 'soffice --version' in the terminal.
  2. 2. Download Apache OpenOffice version 4.1.11 or later from the official Apache OpenOffice download page (https://www.openoffice.org/download/).
  3. 3. Uninstall the current version of Apache OpenOffice through the system's package manager or by running the uninstaller.
  4. 4. Install the downloaded version 4.1.11 or later by following the installation wizard prompts.
  5. 5. After installation, verify the new version by checking Help > About Apache OpenOffice to confirm the vulnerability is addressed.
Caveat Standard upgrade - ensure any macro-dependent documents are tested for compatibility

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

Fix this in Openoffice Scoped from the published advisory
  • Consultation3.0 h
  • Implementation6.0 h
  • Testing12.0 h
  • Review / QA4.0 h
25.0 hours of engineering $4,200
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,720.

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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-2021-40439 in production — separate from our analysis above.

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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