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Unrestricted File UploadWeakness · CWE-434

CVE-2026-58480

CRITICAL · 9.8 CVSS v3.1 Published 2026-07-08
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click 7 weeks old

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
Blocksy Companion Pro plugin for WordPress before 2.1.47 contains an unauthenticated arbitrary file upload vulnerability that allows attackers to upload executable files by bypassing extension validation in the save_attachments function exposed through the Advanced Reviews feature. Attackers can exploit the Custom Fonts extension's flawed strpos() substring check by uploading double-extension filenames such as shell.woff2.php, causing the validation to pass on the substring match while the web server executes the file as PHP, achieving remote code execution.

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

The Blocksy Companion Pro plugin before version 2.1.47 has an unauthenticated arbitrary file upload vulnerability in the save_attachments function accessible through the Advanced Reviews feature. The Custom Fonts extension uses a flawed strpos() substring check for extension validation that can be bypassed using double-extension filenames like shell.woff2.php, allowing attackers to upload PHP files that execute on the web server, achieving remote code execution.

MitigationImmediately upgrade Blocksy Companion Pro to version 2.1.47 or later to patch the arbitrary file upload vulnerability. Consider disabling the Advanced Reviews feature and Custom Fonts extension until the patch is applied.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

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
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/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. Confirm Blocksy Companion Pro is installed
    Check your WordPress plugins directory for 'blocksy-companion' or 'blocksy-companion-pro' folder, or query the WordPress plugins database table
    Affected if The plugin is present in the system
  2. Identify installed version
    Read the main plugin file (e.g., plugin.php or blocksy-companion.php) and locate the 'Version' header, or query via WP-CLI: wp plugin list --filter='blocksy' --format=json
    Affected if Version is lower than 2.1.47 (e.g., 2.1.46 or earlier)
  3. Verify Advanced Reviews feature status
    Check WordPress theme options or blocksy settings panel for 'Advanced Reviews' feature enablement; this may be stored in theme customizer options or a database option with 'blocksy' prefix
    Affected if Advanced Reviews feature is enabled and the plugin version is below 2.1.47
  4. Check Custom Fonts extension status
    Inspect the Custom Fonts extension configuration in Blocksy settings or check for custom-fonts related database options; the vulnerable strpos() check applies to font file uploads in this extension
    Affected if Custom Fonts extension is enabled and the plugin version is below 2.1.47
  5. Audit uploaded files for suspicious extensions
    Search wp-content/uploads directories for files with double extensions (e.g., *.woff2.php, *.ttf.php, *.otf.php) or PHP files in font/upload directories using: find /path/to/wp-content/uploads -name '*.php' -o -name '*.woff2.php'
    Affected if Any PHP files or double-extension files exist in upload directories, especially in font-related paths

You are affected if Blocksy Companion Pro version is below 2.47 and either the Advanced Reviews feature or Custom Fonts extension is enabled, or if suspicious double-extension PHP files are found in uploads.

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
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Immediately upgrade Blocksy Companion Pro to version 2.1.47 or later to patch the arbitrary file upload vulnerability. Consider disabling the Advanced Reviews feature and Custom Fonts extension until the patch is applied.

Recommended fix Moderate confidence

Blocksy Companion Pro version 2.1.47 or later

  1. 1. Log in to the WordPress admin dashboard
  2. 2. Navigate to Plugins > Installed Plugins
  3. 3. Locate the Blocksy Companion Pro plugin
  4. 4. Check the current version installed
  5. 5. If the installed version is before 2.1.47, update the plugin to version 2.1.47 or later
  6. 6. Verify the update was successful by confirming the new version number

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

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,770
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An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,832.

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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-2026-58480 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