dbcve.org
Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-3220

HIGH · 8.8 CVSS v3.1 Published 2026-05-18
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
95/100
Remediation priority · Urgent
Remotely reachable No privileges

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
The Autoptimize WordPress plugin before 3.1.15, Clearfy Cache WordPress plugin before 2.4.2, Speed Optimizer WordPress plugin before 7.7.9 are vulnerable to unauthenticated Stored Cross-Site Scripting (XSS) due to a predictable replacement hash used during the HTML minification process and abusing a regular expression. This allows an attacker to inject arbitrary HTML attributes in the final HTML output by anticipating the placeholder format.

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

Three WordPress optimization plugins (Autoptimize, Clearfy Cache, Speed Optimizer) are vulnerable to unauthenticated Stored XSS due to a predictable replacement hash used during HTML minification. Attackers can inject arbitrary HTML attributes by anticipating the placeholder format in the minification regex, allowing malicious script execution in user browsers.

MitigationUpdate all three affected plugins to their patched versions (Autoptimize 3.1.15+, Clearfy Cache 2.4.2+, Speed Optimizer 7.7.9+) and verify the minification functionality works correctly post-update.

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
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/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. Identify installed optimization plugins
    Check your WordPress site's wp-content/plugins directory or use WP CLI: 'wp plugin list --status=active' to list active plugins
    Affected if Any of these three plugins are installed and active: Autoptimize, Clearfy Cache, or Speed Optimizer
  2. Check Autoptimize version
    Navigate to WordPress admin > Plugins > Autoptimize, or inspect the plugin main file header in wp-content/plugins/autoptimize/autoptimize.php for 'Version:'
    Affected if Version is below 3.1.15 (e.g., 3.1.14, 3.1.13, etc.)
  3. Check Clearfy Cache version
    Navigate to WordPress admin > Plugins > Clearfy Cache, or inspect the plugin main file header in wp-content/plugins/clearfy-cache/clearfy-cache.php for 'Version:'
    Affected if Version is below 2.4.2 (e.g., 2.4.1, 2.4.0, etc.)
  4. Check Speed Optimizer version
    Navigate to WordPress admin > Plugins > Speed Optimizer, or inspect the plugin main file header in wp-content/plugins/speed-optimizer/speed-optimizer.php for 'Version:'
    Affected if Version is below 7.7.9 (e.g., 7.7.8, 7.7.0, etc.)
  5. Verify HTML minification is enabled
    Check the plugin settings in WordPress admin: Autoptimize > Show Advanced Settings > HTML minification; Clearfy Cache > Minify HTML; Speed Optimizer > HTML Minify - ensure the option is turned ON
    Affected if The HTML minification setting is enabled in the plugin configuration

You are affected if you have any of these three plugins installed with an unpatched version (below 3.1.15 for Autoptimize, below 2.4.2 for Clearfy Cache, below 7.7.9 for Speed Optimizer) AND HTML minification is currently enabled in the plugin settings.

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

Update all three affected plugins to their patched versions (Autoptimize 3.1.15+, Clearfy Cache 2.4.2+, Speed Optimizer 7.7.9+) and verify the minification functionality works correctly post-update.

Recommended fix High confidence

Autoptimize 3.1.15, Clearfy Cache 2.4.2, Speed Optimizer 7.7.9

  1. Check if Autoptimize, Clearfy Cache, or Speed Optimizer plugins are installed on the WordPress site.
  2. Identify the current version of the installed plugin(s).
  3. Update the plugin(s) to the fixed versions: Autoptimize to 3.1.15, Clearfy Cache to 2.4.2, and Speed Optimizer to 7.7.9.
  4. Verify the update was successful and ensure the website functionality remains intact.

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

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
9.0 hours of engineering $1,570
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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-2026-3220 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