CVE-2020-14455
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. Prompting for HTTP Basic Authentication is mishandled, allowing phishing, aka MMSA-2020-0007.
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 Mattermost Desktop App before version 4.4.0 has a vulnerability where HTTP Basic Authentication prompts are mishandled. This improper handling allows attackers to display fraudulent authentication dialogs to users, potentially tricking them into revealing their credentials. This is a client-side phishing vulnerability in the desktop application.
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
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- None
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Determine Mattermost Desktop App versionOpen the app, then navigate to Help > About Mattermost (Windows/Linux) or click the app name in the menu bar and select About Mattermost (macOS). The version number is displayed in the dialog that appears.Affected if The displayed version is below 4.4.0
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Check version via executable or installation directoryLocate the Mattermost executable. On Windows this is typically in C:\Program Files\Mattermost\. Right-click mattermost.exe and select Properties, then check the Details tab. On macOS, right-click Mattermost.app in /Applications and select Get Info. On Linux, check the package metadata or the desktop entry file.Affected if The version property shows a number less than 4.4.0
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Review application logs for version confirmationAccess the app data folder. On Windows: %APPDATA%\Mattermost\logs. On macOS: ~/Library/Logs/Mattermost. On Linux: ~/.config/Mattermost/logs. Open the most recent log file and search for a version string.Affected if The log files confirm a version lower than 4.4.0
If the installed Mattermost Desktop App version is any release prior to 4.4.0, the environment is vulnerable to the HTTP Basic Authentication prompt phishing vulnerability.
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. Users should verify they are running the latest version and organizations should push the update through their deployment infrastructure.
- Consultation1.0 h
- Implementation1.0 h
- Testing2.0 h
- Review / QA1.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2020-14455 — 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-2020-14455 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
- No spam, self-promotion, credentials, or personal data