The Query Monitor plugin for WordPress has Reflected Cross-Site Scripting via Request URI

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

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

EPSS

• CVE-2026-4267: 0.31% estimated exploitation activity in the next 30 days; percentile 23.63 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact The Query Monitor plugin for WordPress is vulnerable to Reflected Cross-Site Scripting via the $SERVER['REQUESTURI'] parameter in all versions up to, and including, 3.20.3 due to insufficient output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that execute if they can successfully trick an Administrator-level user into performing an action such as clicking on a link. On admin requests, the plugin reads user controlled data from $SERVER['REQUESTURI'] and stores it in the request field, then renders request, matchedquery, and querystring through formaturl(). If the attacker supplied string does not contain &, formaturl() returns it without HTML escaping, which allows injected HTML or JavaScript from the request target to be inserted directly into the page inside a <code element and executed in the victim's browser. Patches This issue has been patched in Query Monitor 3.20.4. Credits Many thanks to Dmitrii Ignatyev at…

Published by the source

19 Mar 2026, 19:37 UTC

Last modified by the source

19 Mar 2026, 19:37 UTC

Source last checked

26 Oct 2026, 14:38 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-2xr4-chcf-vmvf

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# Patch Next advisory brief: CVE-2026-4267

Advisory: The Query Monitor plugin for WordPress has Reflected Cross-Site Scripting via Request URI
IDs: CVE-2026-4267, GHSA-2xr4-chcf-vmvf
Record: https://patchnext.com/advisories/cve-2026-4267 (revision 1, source checked 26 Oct 2026, 14:38 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: johnbillion/query-monitor 3.20.4. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist johnbillion/query-monitor: affected < 3.20.4; fixed in 3.20.4

## Suggested inspection (read-only)
- Packagist johnbillion/query-monitor: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on johnbillion/query-monitor.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-2xr4-chcf-vmvf (GitHub-reviewed advisory GHSA-2xr4-chcf-vmvf lists affected ranges: Packagist johnbillion/query-monitor >=0 <3.20.4)

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