CVE-2025-55035
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 · uneditedMattermost Desktop App versions <=5.13.0 fail to manage modals in the Mattermost Desktop App that stops a user with a server that uses basic authentication from accessing their server which allows an attacker that provides a malicious server to the user to deny use of the Desktop App via having the user configure the malicious server and forcing a modal popup that cannot be closed.
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 confidenceMattermost Desktop App versions 5.13.0 and earlier contain a modal management flaw where a malicious server configured by an attacker can trigger an unclosable modal popup. This prevents users from accessing the desktop application, effectively creating a denial-of-service condition through UI manipulation.
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< 5.13.1.0CVSS 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
- High
- Privileges
- None
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/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 checksWork through these to decide whether this CVE applies to you.
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Check Mattermost Desktop App versionOpen the Mattermost Desktop app, then go to Help > About Mattermost Desktop (or click on your profile avatar and select Help > About). Note the version number shown.Affected if The installed version is earlier than 5.13.1.0 (for example, 5.13.0, 5.12.x, etc.)
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Inspect configured serversGo to Settings > Server Management or check the server list in the app. Review all configured server URLs and their display names.Affected if Any configured server is untrusted, unknown, or suspected to be controlled by an attacker.
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Check for stuck modal behaviorAttempt to interact with the app normally. Try clicking outside modals, pressing Escape, or using menu options to close any open dialogs.Affected if A modal popup cannot be closed and blocks all interaction with the application.
You are affected if your Mattermost Desktop version is earlier than 5.13.1.0 AND you have configured a potentially malicious or untrusted server that could trigger the unclosable modal.
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.
dbcve · scoped5.13.1.0
Upgrade to Mattermost Desktop App version 5.14.0 or later. Until upgraded, avoid configuring untrusted servers and revoke any previously added malicious server configurations.
5.13.1.0
- Upgrade Mattermost Desktop App to version 5.13.1.0 or later
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation3.0 h
- Implementation8.0 h
- Testing4.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,800.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-55035 — 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-2025-55035 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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