CVE-2020-11536
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 · uneditedAn issue was discovered in ONLYOFFICE Document Server 5.5.0. An attacker can craft a malicious .docx file, and exploit the unzip function to rewrite a binary and remotely execute code on a victim's server.
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 confidenceONLYOFFICE Document Server 5.5.0 contains a Zip Slip-type vulnerability in its .docx file processing (unzip) function. By crafting a malicious .docx file with path traversal sequences in filenames, an attacker can write arbitrary files to the server's filesystem, overwriting binaries and achieving remote code execution.
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= 5.5.0CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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 checksWork through these to decide whether this CVE applies to you.
-
Verify ONLYOFFICE Document Server is installedCheck for the presence of ONLYOFFICE Document Server components on the system. Look for onlyoffice-related processes, services, or installation directories.Affected if ONLYOFFICE Document Server is present on the system
-
Determine the installed versionUse the appropriate method to query the installed ONLYOFFICE Document Server version (e.g., package manager, installed software list, or version command if available). Compare the result to the affected version 5.5.0.Affected if The installed version is exactly 5.5.0
-
Confirm document processing is enabledVerify that the ONLYOFFICE Document Server document processing service is active and accessible. Check if .docx file upload and conversion features are enabled in the configuration.Affected if The document processing service is running and .docx processing is available to users
-
Check for unauthorized file access indicatorsReview server filesystem logs and audit trails for any unexpected file writes in directories outside the expected document storage area, particularly in system directories or application binary locations.
A system is affected only if ONLYOFFICE Document Server version 5.5.0 is installed and the document processing service is actively processing .docx files.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpgrade ONLYOFFICE Document Server to a version beyond 5.5.0 that includes the security patch. Implement strict input validation and secure archive extraction with allowlist-based path checking before file extraction.
- Consultation4.0 h
- Implementation12.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $7,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-11536 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2020-11536 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
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.
- 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