DiscourseApplication

CVE-2023-36473

MEDIUM · 6.1 CVSS v3.1 Published 2023-07-13
Fix available
A fix is available. Upgrade to 3.0.5 or later.
See remediation →
68/100
Remediation priority · Elevated
Remotely reachable No privileges

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 · unedited
Discourse is an open source discussion platform. A CSP (Content Security Policy) nonce reuse vulnerability could allow XSS attacks to bypass CSP protection. There are no known XSS vectors at the moment, but should one be discovered, this vulnerability would allow the XSS attack to completely bypass CSP. The vulnerability is patched in the latest tests-passed, beta and stable branches.

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 confidence

Discourse contains a Content Security Policy (CSP) nonce reuse vulnerability. The CSP nonce mechanism, designed to prevent XSS attacks by allowing only whitelisted script execution, has a flaw that could allow XSS attacks to completely bypass CSP protection if an XSS vector is discovered.

MitigationUpgrade Discourse to the latest tests-passed, beta, or stable branch which contains the patch for this vulnerability.

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
DiscourseApplication
Affected:< 3.0.5= 1.1.0= 1.2.0= 1.3.0= 1.4.0= 1.5.0= 1.6.0= 1.7.0= 1.8.0= 1.9.0= 2.0.0= 2.1.0

CVSS 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 checks

Work through these to decide whether this CVE applies to you.

  1. Determine Discourse version
    Access the Discourse admin panel and navigate to /admin/about, or check the VERSION file in the Discourse root directory if you have server access
    Affected if The installed version is lower than 3.0.5, or matches any of these: 1.1.0, 1.2.0, 1.3.0, 1.4.0, 1.5.0, 1.6.0, 1.7.0, 1.8.0, 1.9.0, 2.0.0, or 2.1.0
  2. Confirm CSP is active
    Send a request to your Discourse instance and inspect the Content-Security-Policy HTTP response header
    Affected if CSP headers are present and the nonce mechanism is in use, but the Discourse version is vulnerable as determined above

You are affected if your installed Discourse version is less than 3.0.5 or matches any of the specific 1.x/2.x versions listed, since the CSP nonce reuse flaw exists in those versions.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

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 · scoped
Upgrade available Upgrade to 3.0.5 or later
Fixed in 3.0.5
Interim mitigation

Upgrade Discourse to the latest tests-passed, beta, or stable branch which contains the patch for this vulnerability.

Recommended fix High confidence

3.0.5 or later (latest stable/beta/tests-passed branch)

  1. 1. Backup your current Discourse installation and database
  2. 2. Update Discourse to the latest stable release by running ./discourse-upgrade or following the standard upgrade procedure
  3. 3. Verify the upgrade was successful by checking the Discourse admin panel
  4. 4. Confirm the version number reflects the patched release (3.0.5 or later)
Caveat Standard Discourse upgrade risks apply - review release notes for breaking changes between versions

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Discourse Scoped from the published advisory
  • Consultation2.0 h
  • Implementation3.0 h
  • Testing2.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,420
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,272.

Scan for this in your stack

Free · runs locally
dbcve dependency scanner

Check whether your project pulls in CVE-2023-36473 — 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 sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-36473 in production — separate from our analysis above.

No notes yet

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What this is

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.

What belongs here
  • 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