{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.7.12"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "october/system"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.7.13"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 4.0.11"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "october/system"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "4.0.0"
            },
            {
              "fixed": "4.0.12"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2025-61676"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-01-09T20:12:24Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "A cross-site scripting (XSS) vulnerabilities was identified in October CMS backend configuration forms:\n\n- **Branding and Appearances Styles**  \n   A user with the `Customize Backend Styles` permission could inject malicious HTML/JS into the stylesheet input at  \n   *Settings \u2192 Branding \u0026 Appearance \u2192 Styles*.  \n\nA specially crafted input could break out of the intended `\u003cstyle\u003e` context, allowing arbitrary script execution across backend pages for all users.\n\n---\n\n### Impact\n- Persistent XSS across the backend interface.  \n- Exploitable by lower-privileged accounts with the above permissions.  \n- Potential consequences include privilege escalation, session hijacking, and execution of unauthorized actions in victim sessions.\n\n---\n\n### Patches\nThe vulnerability has been patched in **v4.0.12** and **v3.7.13**.  \nStylesheet inputs are now sanitized to prevent injection of arbitrary HTML/JS.  \n\nAll users are strongly encouraged to upgrade to the latest patched version.\n\n---\n\n### Workarounds\nIf upgrading immediately is not possible:  \n- Restrict the permissions `Customize Backend Styles` to fully trusted administrators only.  \n\nThis reduces exposure but does not fully eliminate risk.\n\n---\n\n### Credits\n- Reported by **[Nakkouch Tarek](https://github.com/nakkouchtarek)**",
  "id": "GHSA-wvpq-h33f-8rp6",
  "modified": "2026-01-09T20:12:24Z",
  "published": "2026-01-09T20:12:24Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/octobercms/october/security/advisories/GHSA-wvpq-h33f-8rp6"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/octobercms/october"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "October CMS Vulnerable to Stored XSS via Branding Styles"
}

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "October is a Content Management System (CMS) and web platform. Prior to versions 3.7.13 and 4.0.12, a cross-site scripting (XSS) vulnerabilities was identified in October CMS backend configuration forms. A user with the Customize Backend Styles permission could inject malicious HTML/JS into the stylesheet input at Styles from Branding \u0026 Appearance settings. A specially crafted input could break out of the intended \u003cstyle\u003e context, allowing arbitrary script execution across backend pages for all users. This issue has been patched in versions 3.7.13 and 4.0.12."
    }
  ],
  "id": "CVE-2025-61676",
  "lastModified": "2026-01-10T04:16:00.850",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 6.1,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "HIGH",
          "privilegesRequired": "HIGH",
          "scope": "UNCHANGED",
          "userInteraction": "REQUIRED",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 0.9,
        "impactScore": 5.2,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-01-10T04:16:00.850",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/octobercms/october/security/advisories/GHSA-wvpq-h33f-8rp6"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}