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XenforoApplication

CVE-2025-71278

HIGH · 8.8 CVSS v3.1 Published 2026-04-01
Fix available
A fix is available. Upgrade to 2.3.5 or later.
See remediation →
94/100
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
XenForo before 2.3.5 allows OAuth2 client applications to request unauthorized scopes. This affects any customer using OAuth2 clients on any version of XenForo 2.3 prior to 2.3.5, potentially allowing client applications to gain access beyond their intended authorization level.

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 · moderate confidence

XenForo before 2.3.5 contains an OAuth2 scope validation flaw where client applications can request scopes beyond what they were originally authorized for. This allows potential privilege escalation where malicious or misconfigured OAuth2 clients could gain access to user data or functionality超出其预期权限范围.

MitigationUpgrade XenForo to version 2.3.5 or later to obtain the patched OAuth2 scope validation. Review existing OAuth2 client configurations and authorized scopes post-upgrade to ensure no unauthorized access occurred.

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
XenforoApplication
Affected:>= 2.3.0, < 2.3.5

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
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/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 your XenForo version
    Access the XenForo admin control panel and navigate to Dashboard, or inspect the file /src/XF.php and look for the version constant
    Affected if The installed version is 2.3.0, 2.3.1, 2.3.2, 2.3.3, or 2.3.4 (any version >= 2.3.0 and < 2.3.5)
  2. Verify OAuth2 is enabled
    In the admin panel, go to Setup > OAuth2 or check your config.php file for OAuth2-related settings
    Affected if OAuth2 is enabled and configured in your XenForo installation
  3. Review OAuth2 client scope configurations
    In the admin panel, navigate to OAuth2 > Clients and examine each configured client to see which scopes are assigned to them
    Affected if There are OAuth2 clients configured with any scope assignments
  4. Inspect OAuth2 authorization records
    Check the database table xf_oauth_authorization or the admin panel OAuth2 authorization logs for existing user authorizations and their granted scopes
    Affected if There are existing OAuth2 authorizations showing scopes that differ from what was originally intended for the client

You are affected if your XenForo version is 2.3.0 through 2.3.4 and OAuth2 is enabled with any configured clients or existing authorizations.

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 2.3.5 or later
Fixed in 2.3.5
Interim mitigation

Upgrade XenForo to version 2.3.5 or later to obtain the patched OAuth2 scope validation. Review existing OAuth2 client configurations and authorized scopes post-upgrade to ensure no unauthorized access occurred.

Recommended fix High confidence

XenForo 2.3.5

  1. 1. Create a complete backup of your XenForo database and all files including the /src and /internal_data directories
  2. 2. Download XenForo version 2.3.5 from the official XenForo members area at xenforo.com
  3. 3. Upload all files from the XenForo 2.3.5 package to your server, overwriting existing files
  4. 4. Navigate to your forum's admin control panel and complete the upgrade process by visiting the root URL (yourforum.com/install/)
  5. 5. Clear all XenForo caches via the admin control panel or by deleting contents of the /internal_data/cache directory
  6. 6. Verify OAuth2 client configurations and ensure all registered clients are using only the scopes they legitimately require
Caveat Review your custom add-ons and OAuth2 client implementations for compatibility with 2.3.5 before deploying to production

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

Fix this in Xenforo Scoped from the published advisory
  • Consultation4.0 h
  • Implementation2.0 h
  • Testing6.0 h
  • Review / QA3.0 h
15.0 hours of engineering $2,600
Get the upgrade done

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,160.

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-2025-71278 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