Vulnerability-Lookup

CVE-2026-63179 (GCVE-0-2026-63179)

Vulnerability from cvelistv5 – Published: 2026-08-26 18:06 – Updated: 2026-08-26 18:51

Title

Winter: Local File Inclusion through @import directives in LESS compilation of backend customizable stylesheets and theme assets

Summary

Winter CMS is a content management system built on the Laravel PHP framework. In versions up to and including 1.2.12, authenticated backend users can disclose arbitrary files readable by the PHP process by injecting @import (inline) directives into LESS source that the backend compiles, because the LESS parser was instantiated without a safe import resolver and fell back to the raw attacker-supplied path when no allowed root matched. The flaw is reachable through four entry points that share the same root cause: the Brand Settings custom_css field, the Editor Settings html_custom_styles field, the Mail Brand Settings colour-picker fields whose values are concatenated into LESS source without escaping, and theme .less, .sass, and .scss assets compiled when served. Both absolute paths and .. traversal outside the asset's own tree were accepted, so an attacker could read any file the web process can access, most significantly the application .env file and the APP_KEY and database credentials it contains. Exploitation requires a backend account holding one of the associated permissions, which are assigned by default to the built-in Developer role. This issue is fixed in version 1.2.13.

Severity

4.9 (Medium)


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

SSVC

Exploitation: none Automatable: no Technical Impact: partial

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-26 18:51 UTC

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/wintercms/winter/security/advi…	x_refsource_CONFIRM
https://github.com/wintercms/storm/commit/af77033…	x_refsource_MISC
https://github.com/wintercms/winter/commit/130f0e…	x_refsource_MISC
https://github.com/wintercms/winter/releases/tag/…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
wintercms	winter	Affected: < 1.2.13	guessed

Show details on NVD website

JSON

To clipboard

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FKIE_CVE-2026-63179

Vulnerability from fkie_nvd - Published: 2026-08-26 19:16 - Updated: 2026-08-26 20:17

Severity

4.9 (Medium) - CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	https://github.com/wintercms/storm/commit/af770331c683e628533a6ec2991285d6e10a4d6c
	security-advisories@github.com	https://github.com/wintercms/winter/commit/130f0ea43e9228bf0d129b481da1cdfbcc4b4456
	security-advisories@github.com	https://github.com/wintercms/winter/releases/tag/v1.2.13
	security-advisories@github.com	https://github.com/wintercms/winter/security/advisories/GHSA-58fp-mcx6-7qf9

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "winter",
          "vendor": "wintercms",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 1.2.13"
            }
          ]
        }
      ],
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    }
  ],
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      "lang": "en",
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    }
  ],
  "id": "CVE-2026-63179",
  "lastModified": "2026-08-26T20:17:56.483",
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GHSA-58FP-MCX6-7QF9

Vulnerability from github – Published: 2026-08-20 18:43 – Updated: 2026-08-20 18:43

Summary

Winter: Local File Inclusion through @import directives in LESS compilation of backend customizable stylesheets and theme assets

Details

Impact

Affected versions of Winter CMS allow authenticated backend users with the following permissions to disclose arbitrary files readable by the PHP process by injecting @import (inline) "<path>" directives into LESS source that the backend compiles. Four entry points share the same root cause:

Brand Settings BrandSetting.custom_css field (backend.manage_branding) — compiled inline into every backend page's <style> block.
Editor Settings EditorSetting.html_custom_styles field (backend.manage_editor) — compiled inline into every backend page's <style> block.
Mail Brand Settings MailBrandSetting colour-picker fields (system.manage_mail_templates) — values are concatenated into LESS source via Less_Parser::ModifyVars() with no escaping, so any value the form validator does not reject can carry an @import directive.
Theme .less/.sass/.scss assets (cms.manage_assets) — compiled through System\Classes\CombineAssets when served, with the same Less_Parser configuration. Both absolute paths and .. traversal escape from the asset's own tree were exploitable.

The leaked content includes any file the web process can read, most importantly the application .env file (disclosing APP_KEY and database credentials).

To actively exploit this issue, an attacker would need an authenticated backend account with one of the permissions listed above. By default these are assigned to the built-in Developer role.

Patches

The root cause is in the wikimedia/less.php integration in Winter Storm: Less_Parser was instantiated without a safe import resolver, and its Less_FileManager::getFilePath() falls back to the raw attacker-supplied path when no candidate root matches. Storm now ships a LessImportResolver that uses the callable form of Less_Parser::SetImportDirs() to refuse any @import whose resolved path lies outside the calling context's allowed roots, defeating both absolute paths and .. traversal at the parser level.

The four sinks have been updated to use the resolver. The three settings models pass no allowed roots (deny-all) because the bundled stylesheets ship no @import directives and the user fields have no legitimate use for them. System\Classes\CombineAssets configures the theme-asset compiler with themes_path(), plugins_path(), and base_path('modules') as allowed roots, preserving real cross-tree imports observed in shipped themes and plugins.

This security issue has been fixed in v1.2.13 (Winter core) and v1.2.13 (Winter Storm).

Workarounds

If you cannot upgrade, apply https://github.com/wintercms/storm/commit/af770331c683e628533a6ec2991285d6e10a4d6c and https://github.com/wintercms/winter/commit/130f0ea43e9228bf0d129b481da1cdfbcc4b4456 manually. As an interim mitigation, remove cms.manage_assets from any non-trusted role and clear any non-empty value from the Brand Settings custom_css and Editor Settings html_custom_styles fields.

References

See https://github.com/octobercms/october/security/advisories/GHSA-3888-q23f-x7qh for the related (but distinct in scope) October CMS advisory addressing the theme-asset compiler path. The Brand/Editor/Mail Brand Settings sinks reported in this advisory are not covered by the October patch.

Credit to Nguyen Van Hiep (@hypnguyen1209) from Lo Security for reporting the issue.

For more information

If you have any questions or comments about this advisory: - Email us at hello@wintercms.com

Severity

4.9 (Medium)


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

Show details on source website

JSON

To clipboard

{
  "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-2026-63179"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-20T18:43:33Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Impact\n\nAffected versions of Winter CMS allow authenticated backend users with the following permissions to disclose arbitrary files readable by the PHP process by injecting `@import (inline) \"\u003cpath\u003e\"` directives into LESS source that the backend compiles. Four entry points share the same root cause:\n\n- **Brand Settings** `BrandSetting.custom_css` field (`backend.manage_branding`) \u2014 compiled inline into every backend page\u0027s `\u003cstyle\u003e` block.\n- **Editor Settings** `EditorSetting.html_custom_styles` field (`backend.manage_editor`) \u2014 compiled inline into every backend page\u0027s `\u003cstyle\u003e` block.\n- **Mail Brand Settings** `MailBrandSetting` colour-picker fields (`system.manage_mail_templates`) \u2014 values are concatenated into LESS source via `Less_Parser::ModifyVars()` with no escaping, so any value the form validator does not reject can carry an `@import` directive.\n- **Theme `.less`/`.sass`/`.scss` assets** (`cms.manage_assets`) \u2014 compiled through `System\\Classes\\CombineAssets` when served, with the same `Less_Parser` configuration. Both absolute paths and `..` traversal escape from the asset\u0027s own tree were exploitable.\n\nThe leaked content includes any file the web process can read, most importantly the application `.env` file (disclosing `APP_KEY` and database credentials).\n\nTo actively exploit this issue, an attacker would need an authenticated backend account with one of the permissions listed above. By default these are assigned to the built-in Developer role.\n\n### Patches\n\nThe root cause is in the `wikimedia/less.php` integration in [Winter Storm](https://github.com/wintercms/storm): `Less_Parser` was instantiated without a safe import resolver, and its `Less_FileManager::getFilePath()` falls back to the raw attacker-supplied path when no candidate root matches. Storm now ships a `LessImportResolver` that uses the callable form of `Less_Parser::SetImportDirs()` to refuse any `@import` whose resolved path lies outside the calling context\u0027s allowed roots, defeating both absolute paths and `..` traversal at the parser level.\n\nThe four sinks have been updated to use the resolver. The three settings models pass no allowed roots (deny-all) because the bundled stylesheets ship no `@import` directives and the user fields have no legitimate use for them. `System\\Classes\\CombineAssets` configures the theme-asset compiler with `themes_path()`, `plugins_path()`, and `base_path(\u0027modules\u0027)` as allowed roots, preserving real cross-tree imports observed in shipped themes and plugins.\n\nThis security issue has been fixed in [v1.2.13](https://github.com/wintercms/winter/commit/130f0ea43e9228bf0d129b481da1cdfbcc4b4456) (Winter core) and [v1.2.13](https://github.com/wintercms/storm/commit/af770331c683e628533a6ec2991285d6e10a4d6c) (Winter Storm).\n\n### Workarounds\n\nIf you cannot upgrade, apply https://github.com/wintercms/storm/commit/af770331c683e628533a6ec2991285d6e10a4d6c and https://github.com/wintercms/winter/commit/130f0ea43e9228bf0d129b481da1cdfbcc4b4456 manually. As an interim mitigation, remove `cms.manage_assets` from any non-trusted role and clear any non-empty value from the Brand Settings `custom_css` and Editor Settings `html_custom_styles` fields.\n\n### References\n\nSee https://github.com/octobercms/october/security/advisories/GHSA-3888-q23f-x7qh for the related (but distinct in scope) October CMS advisory addressing the theme-asset compiler path. The Brand/Editor/Mail Brand Settings sinks reported in this advisory are not covered by the October patch.\n\nCredit to Nguyen Van Hiep ([@hypnguyen1209](https://github.com/hypnguyen1209)) from Lo Security for reporting the issue.\n\n### For more information\n\nIf you have any questions or comments about this advisory:\n- Email us at [hello@wintercms.com](mailto:hello@wintercms.com)",
  "id": "GHSA-58fp-mcx6-7qf9",
  "modified": "2026-08-20T18:43:33Z",
  "published": "2026-08-20T18:43:33Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/wintercms/winter/security/advisories/GHSA-58fp-mcx6-7qf9"
    },
    {
      "type": "WEB",
      "url": "https://github.com/wintercms/storm/commit/af770331c683e628533a6ec2991285d6e10a4d6c"
    },
    {
      "type": "WEB",
      "url": "https://github.com/wintercms/winter/commit/130f0ea43e9228bf0d129b481da1cdfbcc4b4456"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/wintercms/winter"
    },
    {
      "type": "WEB",
      "url": "https://github.com/wintercms/winter/releases/tag/v1.2.13"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Winter: Local File Inclusion through @import directives in LESS compilation of backend customizable stylesheets and theme assets"
}

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.

Action not permitted

CVE-2026-63179 (GCVE-0-2026-63179)

FKIE_CVE-2026-63179

GHSA-58FP-MCX6-7QF9

Impact

Patches

Workarounds

References

For more information

Tags

Sightings

Nomenclature