CI4MS: Stored XSS in Blog Content via Broken html_purify Validation Rule

Exploitation

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

CVSS

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

EPSS

• CVE-2026-45138: 0.18% estimated exploitation activity in the next 30 days; percentile 7.01 (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 custom htmlpurify validation rule used to sanitize blog post bodies relies on by-reference mutation (?string &$str), but CodeIgniter 4's validator passes a local copy of the value, so the sanitized text is silently discarded. The Blog controller writes $lanData['content'] directly into bloglangs.content, and the public template echoes it without escaping — yielding stored XSS executable in any visitor's browser, including the superadmin when previewing or editing posts. Details Root cause: by-reference mutation never propagates Modules\Backend\Validation\CustomRules::htmlpurify declares its first argument by reference: CI4's validator invokes the rule via a local variable $value it created from a copy of $this-data: The reference mutation modifies that local $value only; $this-data, $POST, and getValidated() keep the raw payload. The optional getClean($original) cache lookup in CustomRules.php:85-93 also fails because the cache was keyed on md5(clean) rather than…

Published by the source

18 May 2026, 15:39 UTC

Last modified by the source

18 May 2026, 15:39 UTC

Source last checked

26 Oct 2026, 14:40 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-2m69-jmvh-6chr

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# Patch Next advisory brief: CVE-2026-45138

Advisory: CI4MS: Stored XSS in Blog Content via Broken `html_purify` Validation Rule
IDs: CVE-2026-45138, GHSA-2m69-jmvh-6chr
Record: https://patchnext.com/advisories/cve-2026-45138 (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: Medium (CVSS 5.4)
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-2m69-jmvh-6chr (GitHub-reviewed advisory GHSA-2m69-jmvh-6chr lists affected ranges: Packagist ci4-cms-erp/ci4ms >=0 <=0.31.8.0)

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