CVE-2025-22602
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. In affected versions an attacker can execute arbitrary JavaScript on users' browsers by posting a malicious video placeholder html element. This issue only affects sites with CSP disabled. This problem has been patched in the latest version of Discourse. Users are advised to upgrade. Users unable to upgrade should enable CSP.
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 confidenceA stored XSS vulnerability in Discourse allows attackers to inject arbitrary JavaScript via malicious video placeholder HTML elements. The attack succeeds only when Content Security Policy (CSP) is disabled, as CSP headers would block the malicious script execution.
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< 3.3.4< 3.4.0= 3.4.0CVSS 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
- 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 Discourse versionLog into the Discourse admin panel and navigate to /admin/about, or run `cd /var/discourse && git describe --tags` from the server terminalAffected if version is below 3.3.4, or between 3.3.4 and 3.4.0 exclusive, or exactly 3.4.0
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Verify Content Security Policy statusCheck the Discourse admin panel under /admin/site_settings/category/security for the "content_security_policy" setting, or inspect HTTP responses for the Content-Security-Policy headerAffected if Content Security Policy is disabled or not set (the attack only succeeds when CSP is absent)
You are affected if your installed Discourse version falls within the vulnerable range AND Content Security Policy is disabled, as CSP headers would block script execution from the malicious video placeholder elements.
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 · scoped3.3.43.4.0
Upgrade to the latest patched version of Discourse, or enable Content Security Policy (CSP) as an immediate workaround if unable to upgrade.
3.4.1 or later (or latest 3.3.x stable if on the 3.3.x branch)
- 1. Back up your Discourse instance before performing any upgrade.
- 2. Upgrade Discourse to the latest stable release (version 3.4.1 or later, or the latest 3.3.x stable release if staying on the 3.3.x branch).
- 3. After upgrade, verify the patch is applied by checking that video placeholder HTML elements are properly sanitized.
- 4. As an additional defense layer, enable Content Security Policy (CSP) in your Discourse admin settings if it was previously disabled.
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 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 $2,272.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-22602 — 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-2025-22602 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