Vulnerabilities in pkg:npm/@tdurieux/anonymous_github

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-g485-8j3v-p6x8",
  "modified" : "2026-05-05T18:28:32Z",
  "published" : "2026-05-05T18:28:32Z",
  "aliases" : [ ],
  "summary" : "@tdurieux/anonymous_github Vulnerable to XSS via Unsanitized GitHub Repository Content Rendering in Anonymous GitHub Origin",
  "details" : "### Summary\n\nAnonymous GitHub fetches repository content (e.g., markdown files) from GitHub's API and renders it without sanitization. On the client side, markdown is parsed with `marked` (with `sanitize: false`) and injected into the DOM via `$sce.trustAsHtml()` + `ng-bind-html`, bypassing AngularJS's built-in XSS protection. An attacker can craft a malicious GitHub repository whose README executes arbitrary JavaScript in the Anonymous GitHub origin.\n\n### Details\n\n#### README fetched from GitHub API\n\nThe server fetches the README via GitHub's REST API and stores the raw markdown in MongoDB:\n\n```typescript\n// https://github.com/tdurieux/anonymous_github/blob/b2d77faa6c6f35ad9ae6ed46e3a3fa4681ac84c2/src/core/source/GitHubRepository.ts#L162-L174\nconst ghRes = await oct.repos.getReadme({\n  owner: this.owner,\n  repo: this.repo,\n  ref: selected?.commit,\n});\nconst readme = Buffer.from(\n  ghRes.data.content,\n  ghRes.data.encoding as BufferEncoding\n).toString(\"utf-8\");\nselected.readme = readme;\nawait model.save();\n```\n\nIt is then served to the client with no sanitization:\n\n```typescript\n// https://github.com/tdurieux/anonymous_github/blob/b2d77faa6c6f35ad9ae6ed46e3a3fa4681ac84c2/src/server/routes/repository-private.ts#L254-L260\nreturn res.send(\n  await repo.readme({\n    accessToken: token,\n    force: req.query.force == \"1\",\n    branch: req.query.branch as string,\n  })\n);\n```\n\n#### Client-side rendering via `$sce.trustAsHtml()` + `ng-bind-html`\n\nThe client fetches the raw README, parses it with `renderMD()` (which uses `marked` with `sanitize: false`), then bypasses AngularJS sanitization:\n\n```javascript\n// https://github.com/tdurieux/anonymous_github/blob/b2d77faa6c6f35ad9ae6ed46e3a3fa4681ac84c2/public/script/app.js#L1219-L1226\nconst res = await $http.get(`/api/repo/${o.owner}/${o.repo}/readme`, {\n  params: { force: force === true ? \"1\" : \"0\", branch: $scope.source.branch },\n});\n$scope.readme = res.data;\n```\n\n```javascript\n// https://github.com/tdurieux/anonymous_github/blob/b2d77faa6c6f35ad9ae6ed46e3a3fa4681ac84c2/public/script/app.js#L1339-L1343\nconst html = renderMD(\n  $scope.anonymize_readme,\n  `https://github.com/${o.owner}/${o.repo}/raw/${$scope.source.branch}/`\n);\n$scope.html_readme = $sce.trustAsHtml(html);  // sink: bypasses Angular XSS protection\n```\n\nThe `renderMD()` function explicitly disables sanitization:\n\n```javascript\n// https://github.com/tdurieux/anonymous_github/blob/b2d77faa6c6f35ad9ae6ed46e3a3fa4681ac84c2/public/script/utils.js#L165-L176\nmarked.setOptions({\n  sanitize: false,  // HTML in markdown is preserved as-is\n  // ...\n});\nreturn marked.parse(md, { renderer });\n```\n\nThe resulting HTML is bound to the DOM via `ng-bind-html`, which trusts the string marked by `$sce.trustAsHtml()` and inserts it as innerHTML.\n\n### Impact\n\n1. **Stored XSS**: Any malicious GitHub repository can execute JavaScript in the Anonymous GitHub origin when a user anonymizes it or views its content\n2. **Account Takeover**: Steal authentication tokens and session cookies\n3. **Data Exfiltration**: Access other users' anonymization configurations and private repository data via `/api/user` and `/api/repo/list`\n\n### Proof of Concept\n\n![poc-xss-anonymous-github](https://github.com/user-attachments/assets/c1bf3ed9-4e1e-4c8e-87f0-782a8d5f6ead)\n\n1. Create a GitHub repository with a malicious `README.md`:\n\n```markdown\n# Innocent README\n<img src=x onerror=\"alert(document.domain)\">\n```\n\n2. On Anonymous GitHub, enter the malicious repository URL to anonymize it\n3. The XSS executes immediately when the README preview is rendered on the anonymize page\n\n### Remediation\n\n1. Sanitize markdown output with DOMPurify before rendering (the dependency already exists but is unused)\n2. Serve HTML files with `Content-Disposition: attachment` or in a sandboxed iframe on a separate origin\n3. Replace `$sce.trustAsHtml()` with proper `ngSanitize` usage\n4. HTML-escape filenames and paths in directory listing templates\n5. Add Content Security Policy headers\n\n### Credits\n\nZhengyu Liu, Jingcheng Yang",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "npm",
      "name" : "@tdurieux/anonymous_github"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "2.2.0"
      }, {
        "fixed" : "2.3.0"
      } ]
    } ],
    "versions" : [ "2.2.0" ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/tdurieux/anonymous_github/security/advisories/GHSA-g485-8j3v-p6x8"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/tdurieux/anonymous_github"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79", "CWE-80" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-05-05T18:28:32Z",
    "nvd_published_at" : null
  }
}