CVE-2023-30538
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 · uneditedDiscourse is an open source platform for community discussion. Due to the improper sanitization of SVG files, an attacker can execute arbitrary JavaScript on the users’ browsers by uploading a crafted SVG file. This issue is patched in the latest stable and tests-passed versions of Discourse. Users are advised to upgrade. For users unable to upgrade there are two possible workarounds: enable CDN handing of uploads (and ensure the CDN sanitizes SVG files) or disable SVG file uploads by ensuring that the `authorized extensions` site setting does not include `svg` (or reset that setting to the default, by default Discourse doesn't enable SVG uploads by users).
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 confidenceDue to improper sanitization of SVG file uploads in Discourse, an attacker can upload a crafted SVG file containing malicious JavaScript that executes in users' browsers when they view the uploaded file (stored XSS).
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<= 3.0.2< 3.1.0= 3.1.0CVSS 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
- 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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Identify installed Discourse versionAccess the Discourse admin panel and navigate to /about or check the VERSION file in the Discourse installation directory. The version is typically visible in the footer of the admin dashboard.Affected if The installed version is 3.0.2 or lower, any version below 3.1.0, or exactly 3.1.0
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Verify SVG upload capability is enabledIn the Discourse admin panel, go to the Security settings or Site Settings and look for an option controlling allowed file upload extensions. Check if 'svg' is included in the list of permitted extensions.Affected if SVG files are listed as an allowed/uploadable extension in the Discourse configuration
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Confirm no SVG sanitization CDN is configuredNavigate to the CDN/external storage settings in the Discourse admin panel and verify whether a content sanitization service is configured to process uploaded SVG files before serving them.Affected if No CDN or external sanitization service is configured to sanitize SVG uploads, and SVG uploads remain enabled
You are affected if your Discourse version is 3.1.0 or any version below 3.1.0, and SVG file uploads are currently enabled in your settings with no CDN sanitization layer present.
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 · scoped3.1.0
Upgrade to the latest stable or tests-passed version of Discourse, or alternatively disable SVG uploads by removing 'svg' from authorized extensions, or configure a CDN that sanitizes SVG files.
Upgrade to Discourse 3.1.1 or later (latest stable release)
- Upgrade Discourse to the latest stable version (released after the fix) which is version 3.1.1 or later
- After upgrading, verify that SVG file uploads are properly sanitized
- Confirm the version by checking the Discourse admin panel under /about
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation2.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $1,984.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-30538 — 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-2023-30538 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