CI4MS: Stored XSS in Pages Module Content via Broken html_purify Validation Rule

Exploitation

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

CVSS

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

EPSS

• CVE-2026-45270: 0.26% estimated exploitation activity in the next 30 days; percentile 18.05 (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 The Pages backend module registers the htmlpurify validation rule on language-keyed page content but persists the raw, un-purified POST value into the database. The public renderer for pages (Home::index() → app/Views/templates/default/pages.php) emits $pageInfo-content without esc(), yielding stored XSS that fires for every public visitor of the affected page — including administrators. Because pages may be promoted to the site home page, the payload can be served at / and reach every visitor of the site. Details This is a sibling-module variant of the same root cause as the Blog stored-XSS issue. The htmlpurify custom rule (modules/Backend/Validation/CustomRules.php:54) mutates its first argument by reference: CodeIgniter 4's Validation::processRules() (vendor/codeigniter4/framework/system/Validation/Validation.php:344) invokes the rule as $set-{$rule}($value, $error) where $value is a local copy populated from request data. Even though the rule signature accepts $str by…

Published by the source

18 May 2026, 16:23 UTC

Last modified by the source

18 May 2026, 16:23 UTC

Source last checked

26 Oct 2026, 14:40 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-gqr2-7hcg-rchf

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# Patch Next advisory brief: CVE-2026-45270

Advisory: CI4MS: Stored XSS in Pages Module Content via Broken html_purify Validation Rule
IDs: CVE-2026-45270, GHSA-gqr2-7hcg-rchf
Record: https://patchnext.com/advisories/cve-2026-45270 (revision 1, source checked 26 Oct 2026, 14:40 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.7)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: ci4-cms-erp/ci4ms 0.31.9.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist ci4-cms-erp/ci4ms: affected <= 0.31.8.0; fixed in 0.31.9.0

## Suggested inspection (read-only)
- Packagist ci4-cms-erp/ci4ms: 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 ci4-cms-erp/ci4ms.
- 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-gqr2-7hcg-rchf (GitHub-reviewed advisory GHSA-gqr2-7hcg-rchf lists affected ranges: Packagist ci4-cms-erp/ci4ms >=0 <=0.31.8.0)

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