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Cross-site Scripting (XSS)Weakness · CWE-79

CVE-2026-57671

HIGH · 7.1 CVSS v3.1 Published 2026-07-02
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
78/100
Remediation priority · High
Remotely reachable No privileges 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
Unauthenticated Cross Site Scripting (XSS) in perfmatters <= 2.6.4 versions.

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

Unauthenticated Cross Site Scripting (XSS) vulnerability in the perfmatters WordPress plugin affecting versions 2.6.4 and below. An attacker can inject malicious client-side scripts into web pages viewed by other users without authentication, potentially enabling session hijacking, credential theft, or malicious content injection.

MitigationUpdate perfmatters plugin to a version newer than 2.6.4. If immediate updating is not feasible, implement WAF rules to filter XSS attack patterns and monitor for indicators of compromise.

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
Changed
Confidentiality
Low
Integrity
Low
Availability
Low

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:L

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. Locate perfmatters plugin files
    Access your WordPress site via FTP or file manager and navigate to /wp-content/plugins/ and check if a folder named 'perfmatters' exists
    Affected if the perfmatters folder is missing - the plugin is not installed
  2. Identify installed version
    Open the main plugin file (perfmatters.php) in a text editor and locate the 'Version' header in the plugin comments at the top of the file, or check the WordPress admin dashboard under Plugins > Installed Plugins > perfmatters
    Affected if version number cannot be determined or is 2.6.4 or lower
  3. Confirm plugin is active
    Log into WordPress admin and go to Plugins > Installed Plugins, or query the database table wp_options for option_name = 'active_plugins' and check if perfmatters is listed
    Affected if perfmatters appears in the active plugins list
  4. Verify XSS attack surface
    Since this is an unauthenticated XSS, any public-facing page using perfmatters functionality is potentially affected - no specific configuration toggle controls this vulnerability
    Affected if plugin version is 2.6.4 or lower and the plugin is active on a public site

You are affected if the perfmatters WordPress plugin is installed, active, and running version 2.6.4 or lower.

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.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Update perfmatters plugin to a version newer than 2.6.4. If immediate updating is not feasible, implement WAF rules to filter XSS attack patterns and monitor for indicators of compromise.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing4.0 h
  • Review / QA2.0 h
12.0 hours of engineering $2,080
Get help mitigating

An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,328.

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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-2026-57671 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