CVE-2023-35075
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 fails to use innerText / textContent when setting the channel name in the webapp during autocomplete, allowing an attacker to inject HTML to a victim's page by create a channel name that is valid HTML. No XSS is possible though.
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 webapp fails to safely render channel names in autocomplete by using innerHTML instead of textContent/innerText, allowing HTML injection through malicious channel names. While not exploitable as XSS (no script execution), attackers can inject arbitrary HTML content into victims' pages.
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<= 7.8.12>= 8.0.0, <= 8.1.3CVSS 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 versionLog into the Mattermost server and run 'mattermost version' from the command line, or access the Mattermost API at /api/v4/system/about to retrieve the version fieldAffected if The version returned is either <= 7.8.12 or >= 8.0.0 and <= 8.1.3
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Verify the webapp component versionIn a deployed Mattermost instance, open browser developer tools and inspect the bundled JavaScript file (typically app.*.js) or check the /static/* files in the mattermost-webapp container/package. Look for version identifiers in the build metadataAffected if The webapp build version matches the vulnerable server version ranges ( <= 7.8.12 or >= 8.0.0 and <= 8.1.3 )
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Confirm channel autocomplete feature is accessibleLog into the Mattermost web interface and type a forward slash (/) or the beginning of a channel name in the message input box to trigger the autocomplete dropdownAffected if The autocomplete dropdown appears and renders channel names from the server
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Identify vulnerable code pattern in webapp sourceExamine the Mattermost webapp source code in the component handling channel autocomplete (typically in /components/suggestion/ or similar autocomplete-related components). Search for innerHTML assignments when setting channel name textAffected if The code uses innerHTML to render channel names in the autocomplete suggestion list without prior HTML entity encoding
You are affected if your Mattermost version falls within <= 7.8.12 or >= 8.0.0 and <= 8.1.3 AND users have access to the channel name autocomplete feature which renders channel names via innerHTML.
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 dataReplace innerHTML with textContent or innerText when setting channel name in autocomplete, or implement proper HTML entity encoding before rendering.
- Consultation2.0 h
- Implementation2.0 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-2023-35075 — 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-2023-35075 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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