CompanionApplication · Atlassian
CVE-2020-4020
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 · uneditedThe file downloading functionality in the Atlassian Companion App before version 1.0.0 allows remote attackers, who control a Confluence Server instance that the Companion App is connected to, execute arbitrary .exe files via a Protection Mechanism Failure.
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 confidenceThe Atlassian Companion App before version 1.0.0 contains a protection mechanism failure in its file downloading functionality. An attacker who controls a Confluence Server instance that the Companion App connects to can craft malicious responses that bypass security protections, causing the app to download and execute arbitrary .exe files on the victim's machine.
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
CompanionApplication
< 1.0.0CVSS 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
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:H/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.
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Verify Atlassian Companion installationCheck if the Atlassian Companion application is present on the system. Look for the Companion app in installed programs or running processes.Affected if The application is installed and running.
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Determine installed versionLocate and read the application version information. This is typically found in the application's properties, about section, or installed packages. Compare this version number against the affected range.Affected if The installed version is anything less than 1.0.0.
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Confirm Confluence connectivityVerify whether the Companion App is configured to connect to any Confluence Server instances. Check the app's connection settings or network activity to confirm active or configured connections.Affected if The app has active or configured connections to Confluence Server.
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Assess file download usageDetermine if the file downloading functionality of the Companion App is enabled or has been used. Review any logs or settings related to file transfer or document sync features.Affected if File downloading or document sync features are enabled or have been used.
A user is affected if the Atlassian Companion App version is below 1.0.0 and the app connects to a Confluence Server while file downloading functionality is active.
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 data1.0.0
Upgrade the Atlassian Companion App to version 1.0.0 or later to obtain the patched version that addresses the protection mechanism failure. Verify that the auto-update mechanism correctly deploys the fix to all connected clients.
Fix this in Companion
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing3.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,904.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-4020 — 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-2020-4020 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
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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