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DiscourseApplication

CVE-2023-41042

MEDIUM · 6.5 CVSS v3.1 Published 2023-09-15
Fix available
A fix is available. Upgrade to 3.1.1 or later.
See remediation →
71/100
Remediation priority · Elevated
Remotely reachable Zero-click

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. Prior to version 3.1.1 of the `stable` branch and version 3.2.0.beta1 of the `beta` and `tests-passed` branches, importing a remote theme loads their assets into memory without enforcing limits for file size or number of files. The issue is patched in version 3.1.1 of the `stable` branch and version 3.2.0.beta1 of the `beta` and `tests-passed` branches. There are no known workarounds.

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

Importing remote themes in Discourse versions prior to 3.1.1 (stable) and 3.2.0.beta1 (beta/tests-passed) loads theme assets into memory without enforcing any limits on file size or number of files, allowing attackers to exhaust server memory and cause denial of service.

MitigationUpgrade to Discourse version 3.1.1 (stable) or 3.2.0.beta1 (beta/tests-passed) which implements proper limits on theme asset file sizes and counts during import.

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:< 3.1.1= 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
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/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 checks

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

  1. Check Discourse version
    Access the Discourse admin panel at /admin, or run `git log -1` in the Discourse directory, or check the /version route on the site
    Affected if The installed version is less than 3.1.1 (stable) or 3.2.0.beta1 (beta), 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, 2.1.0
  2. Identify if remote theme import is enabled
    In the Discourse admin panel, navigate to Customize > Themes and look for any themes imported from a remote git repository, or check for the 'import_theme' functionality in the site's API or CLI tools
    Affected if Remote theme import is configured or any remote themes are present in the system
  3. Check for resource exhaustion indicators
    Monitor server memory usage and process logs for unusual memory consumption, particularly around theme-related operations or after theme imports
    Affected if Server memory shows abnormal consumption with no other explanation, or theme import processes are consuming excessive memory

You are affected if your Discourse version is below 3.1.1 (or 3.2.0.beta1) AND remote theme import functionality is in use on the server.

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 3.1.1 or later
Fixed in 3.1.1
Interim mitigation

Upgrade to Discourse version 3.1.1 (stable) or 3.2.0.beta1 (beta/tests-passed) which implements proper limits on theme asset file sizes and counts during import.

Recommended fix High confidence

3.1.1 (stable branch) or 3.2.0.beta1 (beta/tests-passed branch)

  1. Identify the currently running Discourse version and branch (stable, beta, or tests-passed)
  2. If using the stable branch and version is less than 3.1.1, upgrade to version 3.1.1
  3. If using the beta or tests-passed branch and version is less than 3.2.0.beta1, upgrade to version 3.2.0.beta1 or later
  4. Verify the upgrade was successful by checking the Discourse version after update

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

Fix this in Discourse Scoped from the published advisory
  • Consultation2.0 h
  • Implementation8.0 h
  • Testing6.0 h
  • Review / QA4.0 h
20.0 hours of engineering $3,460
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Scan for this in your stack

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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-2023-41042 in production — separate from our analysis above.

No notes yet

Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.

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