CVE-2020-14456
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 Mattermost Desktop App before 4.4.0. The Same Origin Policy is mishandled during access-control decisions for web APIs, aka MMSA-2020-0006.
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 confidenceThe Same Origin Policy (SOP) is a fundamental browser security mechanism that restricts how documents or scripts from one origin can interact with resources from another origin. In Mattermost Desktop App before 4.4.0, SOP is mishandled during access-control decisions for web APIs, allowing cross-origin requests that should be blocked. This could enable attackers to make unauthorized API calls, potentially leading to data theft or actions on behalf of authenticated users.
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< 4.4.0CVSS 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
- Low
- Integrity
- Low
- Availability
- Low
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
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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Locate the Mattermost Desktop App installationOn Windows, check the installed version in Programs and Features or the app's installation directory. On macOS, check /Applications or via the app's Info.plist. On Linux, check via the package manager or the installed binary.Affected if The application is Mattermost Desktop App and the version is less than 4.4.0 or cannot be determined to be 4.4.0 or higher
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Verify the installed version numberLaunch the Mattermost Desktop App and navigate to: Help > Version (or About on some platforms), or right-click the desktop shortcut and select Properties to view version information. The version is typically displayed in the format like 4.x.x.Affected if The displayed version number is any version before 4.4.0 (for example, 4.3.0, 4.2.0, 4.1.0, etc.)
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Confirm web API functionality is accessibleThe vulnerability affects SOP enforcement for web API access. If the Mattermost Desktop App is configured to connect to a Mattermost server and users can interact with the interface (channels, messages, integrations), the web API is in use.Affected if The app is connected to a Mattermost server and web API functionality is active, combined with a version below 4.4.0
A user is affected if Mattermost Desktop App is installed with any version prior to 4.4.0 and is actively connecting to a Mattermost server.
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 data4.4.0
Upgrade Mattermost Desktop App to version 4.4.0 or later to obtain the patched version with correct Same Origin Policy enforcement.
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-14456 — 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-2020-14456 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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- 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
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