CVE-2023-1776
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 · uneditedBoards in Mattermost allows an attacker to upload a malicious SVG image file as an attachment to a card and share it using a direct link to the file.
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 confidenceThis is a stored Cross-Site Scripting (XSS) vulnerability in Mattermost Boards where attackers can upload malicious SVG files containing embedded JavaScript as card attachments and share them via direct links. When users access the shared SVG file, the embedded script executes in their browser.
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< 7.1.6= 7.7.1CVSS 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
- Low
- User interaction
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/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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Check Mattermost Server versionAccess the Mattermost System Console and navigate to the About section, or run 'mattermost version' from the command line if you have server accessAffected if The installed version is less than 7.1.6 or exactly 7.7.1
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Verify Boards plugin is enabledIn Mattermost System Console, go to Plugins > Plugin Management and confirm that the Boards plugin is installed and enabledAffected if Boards plugin is enabled and the server version is in the affected range
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Confirm SVG upload capability in BoardsIn Mattermost Boards, attempt to upload an SVG file as a card attachment, or check the Boards plugin configuration settings for allowed file typesAffected if SVG files can be uploaded as card attachments without sanitization of script elements
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Inspect existing SVG attachments in BoardsSearch the file storage or database for SVG files uploaded to Boards cards, or review shared links to SVG attachments in the Boards interfaceAffected if SVG files with embedded script tags exist as card attachments and are accessible via direct links
A user is affected if their Mattermost Server version is less than 7.1.6 or exactly 7.7.1, Boards is enabled, and SVG file uploads are permitted without content sanitization.
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 · scoped7.1.6
Restrict or block SVG file uploads in Mattermost Boards, implement SVG content sanitization/stripping of script elements, and/or deploy strict Content Security Policy headers to prevent script execution from uploaded files.
Mattermost Server 7.1.6 (for versions < 7.1.6) or 7.7.2+ (for version 7.7.1)
- 1. Backup your Mattermost Server database and configuration files before proceeding.
- 2. Download Mattermost Server version 7.1.6 or later (for versions < 7.1.6), or version 7.7.2 or later (for version 7.7.1).
- 3. Stop the Mattermost Server service.
- 4. Upgrade Mattermost Server using your preferred installation method (e.g., apt-get upgrade, yum update, or manual upgrade).
- 5. Verify the upgrade was successful by checking the server version in System Console > About.
- 6. Test that the Boards functionality works correctly with SVG file uploads.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 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 $4,480.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-1776 — 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-2023-1776 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