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DiscourseApplication

CVE-2025-68662

CRITICAL · 9.9 CVSS v3.1 Published 2026-01-28
Fix available
A fix is available. Upgrade to 3.5.4 / 2025.11.2 or later.
See remediation →
100/100
Remediation priority · Urgent
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. In versions prior to 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0, a hostname validation issue in FinalDestination could allow bypassing SSRF protections under certain conditions. This issue is patched in versions 3.5.4, 2025.11.2, 2025.12.1, and 2026.1.0. No known workarounds are available.

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

A hostname validation flaw in Discourse's FinalDestination component allows bypassing Server-Side Request Forgery (SSRF) protections, potentially enabling attackers to make the application perform requests to internal network resources or unintended external hosts.

MitigationUpgrade Discourse to version 3.5.4, 2025.11.2, 2025.12.1, or 2026.1.0. No workaround exists; the fix must be applied through the patched release.

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:< 3.5.4>= 2025.11.0, < 2025.11.2= 2025.12.0= 2026.1.0

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
Changed
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/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. Determine installed Discourse version
    Run `cd /var/www/discourse && git describe --tags` or check the version file at /var/www/discourse/VERSION. Alternatively, access the Discourse admin panel and look at the /about page or the footer which displays the version.
    Affected if The version is < 3.5.4, or >= 2025.11.0 and < 2025.11.2, or exactly 2025.12.0, or exactly 2026.1.0
  2. Verify FinalDestination component is in use
    Check if the FinalDestination gem is loaded by examining the Gemfile or running `bundle list | grep final_destination` in the Discourse directory. This component handles hostname validation for outbound HTTP requests.
    Affected if FinalDestination is present and used for any feature that makes outbound HTTP requests (webhooks, URL previews, etc.)
  3. Check for SSRF protection configuration
    Examine the Discourse site settings related to FinalDestination at /admin/site_settings/category/security?filter=ssrf or check the discourse_ip_info and discourse_plugin:final_destination settings. Also review any custom hostname validation logic in your Discourse installation.
    Affected if Hostname validation is enabled but the FinalDestination component is running a vulnerable version, allowing bypasses to internal IP ranges or blocked hosts

You are affected if your installed Discourse version falls within the vulnerable ranges AND the FinalDestination component handles outbound requests, which is the default behavior for features like URL previews, webhooks, and Open Graph fetching.

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 3.5.4 / 2025.11.2 or later
Fixed in 3.5.42025.11.2
Interim mitigation

Upgrade Discourse to version 3.5.4, 2025.11.2, 2025.12.1, or 2026.1.0. No workaround exists; the fix must be applied through the patched release.

Recommended fix High confidence

2025.12.1 (or latest stable release 2026.1.0)

  1. Identify your current Discourse version by checking the admin panel or running `DISCOURSE_VERSION` command
  2. Determine which version branch you are on (legacy 3.x or 2025/2026 monthly releases)
  3. For Discourse < 3.5.4: Upgrade to version 3.5.4 or later
  4. For Discourse >= 2025.11.0 and < 2025.11.2: Upgrade to version 2025.11.2 or later
  5. For Discourse 2025.12.0: Upgrade to version 2025.12.1 or later
  6. For Discourse 2026.1.0: Upgrade to version 2026.1.0 (already listed as fixed)
  7. After upgrade, verify the hostname validation in FinalDestination is working correctly
  8. Test that SSRF protections are functioning as expected

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

Fix this in Discourse Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA1.0 h
8.0 hours of engineering $1,390
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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-2025-68662 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