CVE-2026-35056
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 · uneditedXenForo before 2.3.9 and before 2.2.18 allows remote code execution (RCE) by authenticated, but malicious, admin users. An attacker with admin panel access can execute arbitrary code on the server.
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 confidenceXenForo before versions 2.3.9 and 2.2.18 contains an authenticated RCE vulnerability allowing malicious admin users to execute arbitrary code on the server. The vulnerability requires admin panel access but can lead to complete server compromise.
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< 2.2.18>= 2.3.0, < 2.3.9CVSS 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
- High
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:H/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 checksWork through these to decide whether this CVE applies to you.
-
Determine installed XenForo versionLocate the version information in your XenForo installation, typically found in the admin control panel under 'System' > 'Options' > 'Basic board information' or in a version.php file within the src directoryAffected if The installed version is less than 2.2.18, or is 2.3.0 through 2.3.8 (versions 2.3.9 and later, and 2.2.18 and later, are not affected)
-
Identify admin user accountsQuery your XenForo database or access the admin control panel to list administrator accounts. Check for any unauthorized or unexpected admin accountsAffected if Any admin account exists that you did not create or authorize, indicating potential compromise
-
Verify admin panel access controlsReview your web server configuration and XenForo admin.php access restrictions. Check if admin panel is accessible from unintended IP addresses or networksAffected if The admin panel (admin.php) is accessible without proper IP restriction or authentication controls
-
Review recent admin activity logsAccess XenForo admin logs through the admin control panel or examine server access logs for admin.php requests. Look for suspicious template modifications, addon installations, or code execution attemptsAffected if Unfamiliar admin actions, especially related to template editing, addon installation, or PHP code execution, are present in logs
-
Check for unauthorized template modificationsIn the admin panel, navigate to Appearance > Templates and review recent changes. Look for any injected PHP code, system() or exec() calls, or malicious callbacksAffected if Templates contain unfamiliar PHP code, shell execution commands, or code you did not intentionally add
Your environment is affected if XenForo version is below 2.2.18 or between 2.3.0 and 2.3.8 AND an attacker with admin panel access could exploit the authenticated RCE vulnerability.
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 · scoped2.2.182.3.9
Upgrade XenForo to version 2.3.9 or later, or 2.2.18 or later. If immediate upgrade is not possible, restrict admin panel access to trusted personnel and monitor for suspicious admin activity.
XenForo 2.2.18 (for 2.2.x users) or XenForo 2.3.9 (for 2.3.x users)
- Backup your XenForo database and all site files
- Identify your current XenForo 2.x version (check src/XF.php or admin dashboard)
- If running 2.2.x branch: download XenForo 2.2.18 from xenforo.com
- If running 2.3.x branch: download XenForo 2.3.9 from xenforo.com
- Upload the new files to your server, overwriting existing installation files
- Run the XF upgrade script or complete any pending upgrade tasks via the admin control panel
- Clear all caches (Admin CP > Tools > Cache > Clear all)
- Verify the upgrade completed successfully and test admin panel functionality
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation2.0 h
- Implementation3.0 h
- Testing4.0 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 $2,752.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-35056 — 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-2026-35056 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
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.
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