Vulnerability-Lookup

GHSA-V7CF-8GH9-GXMJ

Vulnerability from github – Published: 2026-08-12 14:40 – Updated: 2026-08-12 14:40

Summary

Winter: Stored XSS through Brand Settings custom styles

Details

Impact

Users with the backend.manage_branding ("Customize the back-end") permission can provide custom CSS through Settings → Customize Backend → Styles that is compiled through the LESS CSS parser and rendered on every backend page. Previously, the compiled output was not sanitized, which could have allowed a stored XSS attack.

Although this is a valid security issue, it's important to note that its severity is relatively low. To exploit the vulnerability, an attacker would already need to have trusted access to the Winter CMS backend with a specific administrative permission. The Winter CMS maintainers recommend that the backend.manage_branding permission only be granted to trusted administrators and developers.

A related issue exists in the custom styles field at Settings → Editor Settings → Markup Styles (backend.manage_editor permission), which uses the same rendering mechanism and is addressed separately.

All users are advised to update to the latest version to ensure their systems remain secure.

Patches

This issue has been patched in v1.2.13.

Workarounds

Apply https://github.com/wintercms/winter/commit/d28f0b9474af79cfaa80eeb9d691f7a7c4469720 manually if unable to upgrade to v1.2.13.

Resources

CVE-2025-61676 (identical vulnerability in October CMS, patched in v3.7.13 and v4.0.12)

Severity

8.1 (High)


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

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 1.2.12"
      },
      "package": {
        "ecosystem": "Packagist",
        "name": "winter/wn-backend-module"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "1.2.13"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-32257"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-12T14:40:21Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Impact                                                                                                       \n\nUsers with the `backend.manage_branding` (\"Customize the back-end\") permission can provide custom CSS through **Settings \u2192 Customize Backend \u2192 Styles** that is compiled through the LESS CSS parser and rendered on every backend page. Previously, the compiled output was not sanitized, which could have allowed a stored XSS attack.\n\nAlthough this is a valid security issue, it\u0027s important to note that its severity is relatively low. To exploit the vulnerability, an attacker would already need to have trusted access to the Winter CMS backend with a specific administrative permission. The Winter CMS maintainers recommend that the `backend.manage_branding` permission only be granted to trusted administrators and developers.\n\nA related issue exists in the custom styles field at **Settings \u2192 Editor Settings \u2192 Markup Styles** (`backend.manage_editor` permission), which uses the same rendering mechanism and is addressed separately.\n\nAll users are advised to update to the latest version to ensure their systems remain secure.\n\n### Patches\n\nThis issue has been patched in v1.2.13.\n\n### Workarounds\n\nApply [https://github.com/wintercms/winter/commit/d28f0b9474af79cfaa80eeb9d691f7a7c4469720](https://github.com/wintercms/winter/commit/d28f0b9474af79cfaa80eeb9d691f7a7c4469720) manually if unable to upgrade to v1.2.13.\n\n### Resources\n\n- CVE-2025-61676 (identical vulnerability in October CMS, patched in v3.7.13 and v4.0.12)",
  "id": "GHSA-v7cf-8gh9-gxmj",
  "modified": "2026-08-12T14:40:21Z",
  "published": "2026-08-12T14:40:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/wintercms/winter/security/advisories/GHSA-v7cf-8gh9-gxmj"
    },
    {
      "type": "WEB",
      "url": "https://github.com/wintercms/winter/commit/d28f0b9474af79cfaa80eeb9d691f7a7c4469720"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/wintercms/winter"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Winter: Stored XSS through Brand Settings custom styles"
}

CVE-2026-32257 (GCVE-0-2026-32257)

Vulnerability from cvelistv5 – Published: 2026-08-26 16:45 – Updated: 2026-08-27 14:33

Title

Winter: Stored XSS through Brand Settings custom styles

Summary

Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Prior to 1.2.13, custom CSS supplied through the Brand Settings Styles field by a backend user with the backend.manage_branding permission is compiled by the LESS parser and rendered without sanitization on every backend page, allowing stored cross-site scripting against backend users. This issue is fixed in version 1.2.13.

Severity

8.1 (High)


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

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-27 13:56 UTC

CWE

CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

Assigner

GitHub_M mitre root

References

2 references

URL	Tags
https://github.com/wintercms/winter/security/advi…	x_refsource_CONFIRM
https://github.com/wintercms/winter/commit/d28f0b…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
wintercms	winter	Affected: < 1.2.13

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "adp": [
      {
        "metrics": [
          {
            "other": {
              "content": {
                "id": "CVE-2026-32257",
                "options": [
                  {
                    "Exploitation": "none"
                  },
                  {
                    "Automatable": "no"
                  },
                  {
                    "Technical Impact": "total"
                  }
                ],
                "role": "CISA Coordinator",
                "timestamp": "2026-08-27T13:56:55.434856Z",
                "version": "2.0.3"
              },
              "type": "ssvc"
            }
          }
        ],
        "providerMetadata": {
          "dateUpdated": "2026-08-27T14:33:49.017Z",
          "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
          "shortName": "CISA-ADP"
        },
        "title": "CISA ADP Vulnrichment"
      }
    ],
    "cna": {
      "affected": [
        {
          "product": "winter",
          "vendor": "wintercms",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.2.13"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "Winter is a free, open-source content management system (CMS) based on the Laravel PHP framework. Prior to 1.2.13, custom CSS supplied through the Brand Settings Styles field by a backend user with the backend.manage_branding permission is compiled by the LESS parser and rendered without sanitization on every backend page, allowing stored cross-site scripting against backend users. This issue is fixed in version 1.2.13."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 8.1,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "HIGH",
            "privilegesRequired": "HIGH",
            "scope": "CHANGED",
            "userInteraction": "REQUIRED",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:H/I:H/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-79",
              "description": "CWE-79: Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-26T16:45:12.100Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/wintercms/winter/security/advisories/GHSA-v7cf-8gh9-gxmj",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/wintercms/winter/security/advisories/GHSA-v7cf-8gh9-gxmj"
        },
        {
          "name": "https://github.com/wintercms/winter/commit/d28f0b9474af79cfaa80eeb9d691f7a7c4469720",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/wintercms/winter/commit/d28f0b9474af79cfaa80eeb9d691f7a7c4469720"
        }
      ],
      "source": {
        "advisory": "GHSA-v7cf-8gh9-gxmj",
        "discovery": "UNKNOWN"
      },
      "title": "Winter: Stored XSS through Brand Settings custom styles"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-32257",
    "datePublished": "2026-08-26T16:45:12.100Z",
    "dateReserved": "2026-03-11T15:05:48.396Z",
    "dateUpdated": "2026-08-27T14:33:49.017Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.

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