CI4MS: Stored Cross‑Site Scripting (Stored XSS) in Backend User Management Allows Session Hijacking and Full Administrative Account Compromise

Exploitation

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

CVSS

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

EPSS

• CVE-2026-34571: 0.40% estimated exploitation activity in the next 30 days; percentile 34.28 (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 critical Stored Cross-Site Scripting (Stored XSS) vulnerability exists in the backend user management functionality. The application fails to properly sanitize user-controlled input before rendering it in the administrative interface, allowing attackers to inject persistent JavaScript code. This results in automatic execution whenever backend users access the affected page, enabling session hijacking, privilege escalation, and full administrative account compromise. --- Details The vulnerability resides in the backend user creation feature accessible via: User-supplied input in the name and surname fields is stored without proper validation or sanitization. When this data is later rendered in the backend users listing page, it is injected directly into the HTML without output encoding. Because of this, attackers can embed malicious JavaScript payloads that execute in the context of authenticated backend users. This indicates missing contextual output escaping (e.g., HTML…

Published by the source

1 Apr 2026, 22:09 UTC

Last modified by the source

6 Apr 2026, 17:16 UTC

Source last checked

26 Oct 2026, 14:39 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-fc4p-p49v-r948

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# Patch Next advisory brief: CVE-2026-34571

Advisory: CI4MS: Stored Cross‑Site Scripting (Stored XSS) in Backend User Management Allows Session Hijacking and Full Administrative Account Compromise
IDs: CVE-2026-34571, GHSA-fc4p-p49v-r948
Record: https://patchnext.com/advisories/cve-2026-34571 (revision 1, source checked 26 Oct 2026, 14:39 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Critical (CVSS 9.9)
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 0.31.0.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Packagist ci4-cms-erp/ci4ms: affected <= 0.28.6.0; fixed in 0.31.0.0

## 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-fc4p-p49v-r948 (GitHub-reviewed advisory GHSA-fc4p-p49v-r948 lists affected ranges: Packagist ci4-cms-erp/ci4ms >=0 <=0.28.6.0)

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