{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "wger is a free, open-source workout and fitness manager. In versions 2.5 and below, the attribution_link property in AbstractLicenseModel constructs HTML by directly interpolating user-controlled license fields (such as license_author) without escaping, and templates render the result using Django\u0027s |safe filter. An authenticated user can create an ingredient with a malicious license_author value containing JavaScript, which executes in the browser of any visitor viewing the ingredient page, resulting in stored XSS. This issue has been fixed in version 2.5."
    }
  ],
  "id": "CVE-2026-40353",
  "lastModified": "2026-04-17T22:16:33.077",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 5.1,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "LOW",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "LOW",
          "subIntegrityImpact": "LOW",
          "userInteraction": "PASSIVE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "NONE",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-04-17T22:16:33.077",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/wger-project/wger/releases/tag/2.5"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/wger-project/wger/security/advisories/GHSA-6f54-qjvm-wwq3"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "wger"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "last_affected": "2.4"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-40353"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-16T01:37:21Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "# Stored XSS via Unescaped License Attribution Fields\n\n## Summary\n\nThe `AbstractLicenseModel.attribution_link` property in `wger/utils/models.py` constructs HTML strings by directly interpolating user-controlled fields (`license_author`, `license_title`, `license_object_url`, `license_author_url`, `license_derivative_source_url`) without any escaping. The resulting HTML is rendered in the ingredient view template using Django\u0027s `|safe` filter, which disables auto-escaping. An authenticated user can create an ingredient with a malicious `license_author` value containing JavaScript, which executes when any user (including unauthenticated visitors) views the ingredient page.\n\n## Severity\n\n**High** (CVSS 3.1: ~7.6)\n\n- Low-privilege attacker (any authenticated non-temporary user)\n- Stored XSS \u2014 persists in database\n- Triggers on a public page (no authentication needed to view)\n- Can steal session cookies, perform actions as other users, redirect to phishing\n\n## CWE\n\nCWE-79: Improper Neutralization of Input During Web Page Generation (\u0027Cross-site Scripting\u0027)\n\n## Affected Components\n\n### Vulnerable Property\n**File:** `wger/utils/models.py:88-110`\n\n```python\n@property\ndef attribution_link(self):\n    out = \u0027\u0027\n    if self.license_object_url:\n        out += f\u0027\u003ca href=\"{self.license_object_url}\"\u003e{self.license_title}\u003c/a\u003e\u0027\n    else:\n        out += self.license_title  # NO ESCAPING\n    out += \u0027 by \u0027\n    if self.license_author_url:\n        out += f\u0027\u003ca href=\"{self.license_author_url}\"\u003e{self.license_author}\u003c/a\u003e\u0027\n    else:\n        out += self.license_author  # NO ESCAPING\n    out += f\u0027 is licensed under \u003ca href=\"{self.license.url}\"\u003e{self.license.short_name}\u003c/a\u003e\u0027\n    if self.license_derivative_source_url:\n        out += (\n            f\u0027/ A derivative work from \u003ca href=\"{self.license_derivative_source_url}\"\u003ethe \u0027\n            f\u0027original work\u003c/a\u003e\u0027\n        )\n    return out\n```\n\n### Unsafe Template Rendering\n**File:** `wger/nutrition/templates/ingredient/view.html`\n\n- **Line 171:** `{{ ingredient.attribution_link|safe }}`\n- **Line 226:** `{{ image.attribution_link|safe }}`\n\n### Writable Entry Point\n**File:** `wger/nutrition/views/ingredient.py:154-175`\n\n```python\nclass IngredientCreateView(WgerFormMixin, CreateView):\n    model = Ingredient\n    form_class = IngredientForm  # includes license_author field\n```\n\n**URL:** `login_required(ingredient.IngredientCreateView.as_view())` \u2014 any authenticated non-temporary user.\n\n**Form fields (from `wger/nutrition/forms.py:295-313`):** includes `license_author` (TextField, max_length=3500) \u2014 no sanitization.\n\n### Models Affected\n\n6 models inherit from `AbstractLicenseModel`:\n- `Exercise`, `ExerciseImage`, `ExerciseVideo`, `Translation` (exercises module)\n- `Ingredient`, `Image` (nutrition module)\n\nOnly the **Ingredient** and nutrition **Image** models\u0027 attribution links are currently rendered with `|safe` in templates.\n\n## Root Cause\n\n1. `attribution_link` constructs raw HTML by string interpolation of user-controlled fields without calling `django.utils.html.escape()` or `django.utils.html.format_html()`\n2. The template renders the result with `|safe`, bypassing Django\u0027s auto-escaping\n3. The `license_author` field in `IngredientForm` has no input sanitization\n4. The `set_author()` method only sets a default value if the field is empty \u2014 it does not sanitize user-provided values\n\n## Reproduction Steps (Verified)\n\n### Prerequisites\n- A wger instance with user registration enabled (default)\n- An authenticated user account (non-temporary)\n\n### Steps\n\n1. **Register/login** to a wger instance\n\n2. **Create a malicious ingredient** via the web form at `/en/nutrition/ingredient/add/`:\n   - Set `Name` to any valid name (e.g., \"XSS Form Verified\")\n   - Set `Energy` to `125`, `Protein` to `10`, `Carbohydrates` to `10`, `Fat` to `5` (energy must approximately match macros)\n   - Set `Author(s)` (license_author) to:\n     ```\n     \u003cimg src=x onerror=\"alert(document.cookie)\"\u003e\n     ```\n   - Submit the form \u2014 **the form validates and saves successfully with no sanitization**\n\n3. **View the ingredient page** (public URL, no auth needed):\n   - Navigate to the newly created ingredient\u0027s detail page\n   - The XSS payload executes in the browser\n\n### Verified PoC Output\n\nThe rendered HTML in the ingredient detail page (line 171 of `ingredient/view.html`) contains:\n\n```html\n\u003csmall\u003e\n     by \u003cimg src=x onerror=alert(1)\u003e is licensed under \u003ca href=\"https://creativecommons.org/licenses/by-sa/3.0/deed.en\"\u003eCC-BY-SA 3\u003c/a\u003e\n\u003c/small\u003e\n```\n\nThe `\u003cimg\u003e` tag with `onerror` handler is injected directly into the page DOM and executes JavaScript when the browser attempts to load the non-existent image.\n\n### Alternative API Path (ExerciseImage)\n\nFor users who are \"trustworthy\" (account \u003e3 weeks old + verified email):\n\n```bash\n# Upload exercise image with XSS in license_author\ncurl -X POST https://wger.example.com/api/v2/exerciseimage/ \\\n  -H \"Authorization: Token \u003ctoken\u003e\" \\\n  -F \"exercise=1\" \\\n  -F \"image=@photo.jpg\" \\\n  -F \u0027license_author=\u003cimg src=x onerror=\"alert(document.cookie)\"\u003e\u0027 \\\n  -F \"license=2\"\n```\n\nNote: ExerciseImage\u0027s `attribution_link` is not currently rendered with `|safe` in exercise templates, but the data is stored with XSS payloads and would execute if any template renders it with `|safe` in the future. The API serializer also returns the unescaped `attribution_link` data, which could cause XSS in API consumers (mobile apps, SPAs).\n\n## Impact\n\n- **Session hijacking**: Steal admin session cookies to gain full control\n- **Account takeover**: Modify other users\u0027 passwords or email addresses\n- **Data theft**: Access other users\u0027 workout plans, nutrition data, and personal measurements\n- **Worm-like propagation**: Malicious ingredient could inject XSS that creates more malicious ingredients\n- **Phishing**: Redirect users to fake login pages\n\n## Suggested Fix\n\nReplace the `attribution_link` property with properly escaped HTML using Django\u0027s `format_html()`:\n\n```python\nfrom django.utils.html import format_html, escape\n\n@property\ndef attribution_link(self):\n    parts = []\n\n    if self.license_object_url:\n        parts.append(format_html(\u0027\u003ca href=\"{}\"\u003e{}\u003c/a\u003e\u0027, self.license_object_url, self.license_title))\n    else:\n        parts.append(escape(self.license_title))\n\n    parts.append(\u0027 by \u0027)\n\n    if self.license_author_url:\n        parts.append(format_html(\u0027\u003ca href=\"{}\"\u003e{}\u003c/a\u003e\u0027, self.license_author_url, self.license_author))\n    else:\n        parts.append(escape(self.license_author))\n\n    parts.append(format_html(\n        \u0027 is licensed under \u003ca href=\"{}\"\u003e{}\u003c/a\u003e\u0027,\n        self.license.url, self.license.short_name\n    ))\n\n    if self.license_derivative_source_url:\n        parts.append(format_html(\n            \u0027/ A derivative work from \u003ca href=\"{}\"\u003ethe original work\u003c/a\u003e\u0027,\n            self.license_derivative_source_url\n        ))\n\n    return mark_safe(\u0027\u0027.join(str(p) for p in parts))\n```\n\nAlternatively, remove the `|safe` filter from the templates and escape in the property, though this would break the anchor tags.\n\n## References\n\n- [Django Security: Cross Site Scripting (XSS) protection](https://docs.djangoproject.com/en/5.0/topics/security/#cross-site-scripting-xss-protection)\n- [Django `format_html()` documentation](https://docs.djangoproject.com/en/5.0/ref/utils/#django.utils.html.format_html)\n- [OWASP: Stored Cross-Site Scripting](https://owasp.org/www-community/attacks/xss/#stored-xss-attacks)",
  "id": "GHSA-6f54-qjvm-wwq3",
  "modified": "2026-04-16T01:37:21Z",
  "published": "2026-04-16T01:37:21Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/wger-project/wger/security/advisories/GHSA-6f54-qjvm-wwq3"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/wger-project/wger"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:P/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "wger has Stored XSS via Unescaped License Attribution Fields"
}