CVE-2020-35305
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 · uneditedCross site scripting (XSS) in gollum 5.0 to 5.1.2 via the filename parameter to the 'New Page' dialog.
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 confidenceGollum versions 5.0 through 5.1.2 contain a stored cross-site scripting (XSS) vulnerability in the 'New Page' dialog. The filename parameter is not properly sanitized before being rendered, allowing an attacker to inject malicious JavaScript that executes in the browser of users who view the created 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>= 5.0.0, <= 5.1.2CVSS 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
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/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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Identify Gollum installation and versionRun 'gem list gollum' to list the installed gollum gem version, or check your Gemfile/Gemfile.lock for the gollum gem versionAffected if The installed version is >= 5.0.0 and <= 5.1.2
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Verify the New Page feature is accessibleCheck if the '/new' route or 'New Page' dialog is available in your Gollum web interface. This is typically at path '/new' or accessible via the web UI.Affected if The New Page functionality is enabled and accessible to users
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Inspect page creation behaviorAttempt to create a new page using the web interface and examine how the filename is handled. Check if special characters in the filename are reflected in the rendered output without encoding.Affected if The filename parameter is rendered without proper sanitization or encoding in the output
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Review recent Gollum pages for suspicious filenamesExamine the git repository backing Gollum for pages with unusual filenames containing JavaScript patterns like '<script>', 'javascript:', 'onerror=', or other XSS vectorsAffected if Any pages exist with potentially malicious filenames that could execute JavaScript
You are affected if Gollum version 5.0.0 to 5.1.2 is installed AND the New Page feature is enabled, allowing unauthenticated or authenticated users to create pages with malicious filenames.
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 dataUpgrade gollum to version 5.1.3 or later. As an interim measure, disable the 'New Page' functionality or implement output encoding on the filename parameter in the view layer.
- Consultation2.0 h
- Implementation3.0 h
- Testing2.0 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 $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2020-35305 — 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-2020-35305 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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