CVE-2021-3346
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 · uneditedForis before 101.1.1, as used in Turris OS, lacks certain HTML escaping in the login template.
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 confidenceThis is a Cross-Site Scripting (XSS) vulnerability in the Foris web interface used by Turris OS routers. The login template fails to properly escape HTML characters, allowing attackers to inject malicious scripts that execute in victim browsers when they access the login page.
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< 101.1CVSS 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
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/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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Verify Foris is installed on the Turris OS routerCheck if the Foris package exists on the router by listing installed packages or querying the package manager (opkg list-installed | grep foris)Affected if Foris package is not present, then the vulnerability does not apply
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Determine the installed Foris versionRun the package manager query to retrieve the exact version number of the installed Foris package (opkg list-installed | grep foris)Affected if The displayed version number is lower than 101.1, indicating the installed version is affected
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Confirm the Foris web interface is enabled and accessibleCheck the router's configuration or services status to verify the Foris web interface daemon (foris-controller or lighttpd/nginx serving Foris) is running and the login page is accessible over HTTP/HTTPSAffected if The Foris web interface is disabled or not accessible, the XSS vulnerability cannot be triggered even on vulnerable versions
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Identify if the login template lacks proper HTML escapingInspect the Foris login template source code (typically in /www/foris or similar web root directory) to verify whether HTML special characters are being escaped before rendering in the login formAffected if The login template contains unescaped user-controlled input (e.g., error messages, username field) and the Foris version is below 101.1, the XSS vulnerability is present
The environment is affected if Foris version is below 101.1 AND the Foris web interface login page is accessible and renders unescaped HTML in the login template.
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 · scoped101.1
Upgrade Foris to version 101.1.1 or later which implements proper HTML escaping in the login template.
Foris 101.1.1
- Access the Turris router administration interface
- Navigate to the Foris web interface settings
- Check the current Foris version under system information
- Upgrade Foris to version 101.1.1 or later through the router's package management system
- Verify the upgrade completed successfully and the version is now 101.1.1 or higher
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
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Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-3346 — 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-2021-3346 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
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