phpMyFAQ has Stored XSS in Admin FAQ Editor via HTML Entity Bypass in Frontend FAQ Submission

Exploitation

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

CVSS

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

EPSS

• CVE-2026-56736: 0.24% estimated exploitation activity in the next 30 days; percentile 15.71 (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.

Summary A stored cross-site scripting (XSS) vulnerability in phpMyFAQ allows any unauthenticated user (or low-privileged registered user) to inject arbitrary JavaScript that executes in an administrator's browser when they review or edit a user-submitted FAQ entry. This leads to admin account takeover via session theft. The vulnerability exists because htmlentitydecode() converts HTML entities into executable HTML after striptags() has already passed them through, and the admin template renders the content with Twig's |raw filter without any output sanitization. Details Vulnerable file: phpmyfaq/src/phpMyFAQ/Controller/Frontend/Api/FaqController.php (lines 109-115) Root cause: Filter::filterVar() with FILTERSANITIZESPECIALCHARS internally calls filterSanitizeString() which applies striptags() to remove HTML tags. However, striptags() only removes actual HTML tag syntax (e.g., <script) — it does NOT remove HTML entities (e.g., &lt;script&gt;). When enableWysiwygEditorFrontend is true,…

Published by the source

24 Sep 2026, 19:28 UTC

Last modified by the source

24 Sep 2026, 19:45 UTC

Source last checked

26 Oct 2026, 14:53 UTC

1. Revision 2 · amended · 26 Oct 2026

   Amended from ghsa record GHSA-pgwp-vc7q-cvj3

2. Revision 1 · created · 24 Oct 2026

   Published from osv record GHSA-pgwp-vc7q-cvj3

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# Patch Next advisory brief: CVE-2026-56736

Advisory: phpMyFAQ has Stored XSS in Admin FAQ Editor via HTML Entity Bypass in Frontend FAQ Submission
IDs: CVE-2026-56736, GHSA-pgwp-vc7q-cvj3
Record: https://patchnext.com/advisories/cve-2026-56736 (revision 2, source checked 26 Oct 2026, 14:53 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.2)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: phpmyfaq/phpmyfaq 4.2.0-alpha; thorsten/phpmyfaq 4.2.0-alpha. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist phpmyfaq/phpmyfaq: affected < 4.2.0-alpha; fixed in 4.2.0-alpha
- Packagist thorsten/phpmyfaq: affected < 4.2.0-alpha; fixed in 4.2.0-alpha

## Suggested inspection (read-only)
- Packagist phpmyfaq/phpmyfaq: check the installed version with your package manager.
- Packagist thorsten/phpmyfaq: 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 phpmyfaq/phpmyfaq, thorsten/phpmyfaq.
- 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://osv.dev/vulnerability/GHSA-pgwp-vc7q-cvj3 (OSV record GHSA-pgwp-vc7q-cvj3 lists affected ranges: Packagist thorsten/phpmyfaq >=0 =0 <4.2.0-alpha (fixed))
- Verified: https://github.com/advisories/GHSA-pgwp-vc7q-cvj3 (GitHub-reviewed advisory GHSA-pgwp-vc7q-cvj3 lists affected ranges: Packagist thorsten/phpmyfaq >=0 =0 <4.2.0-alpha)

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