{"id":"GHSA-9jj8-v89v-xjvw","summary":"changedetection.io is vulnerable to unauthenticated static path traversal","details":"## Summary\nThe `/static/\u003cgroup\u003e/\u003cfilename\u003e` route accepts `group=\"..\"`, which causes `send_from_directory(\"static/..\", filename)` to execute. This moves the base directory up to `/app/changedetectionio`, enabling **unauthenticated local file read** of application source files (e.g., `flask_app.py`). Severity is **low information disclosure (C:L)**.\n\n### Details\nThe vulnerable code is in `changedetectionio/flask_app.py` inside `static_content()`:\n\n```\ngroup = re.sub(r'[^\\w.-]+', '', group.lower())\nfilename = re.sub(r'[^\\w.-]+', '', filename.lower())\n...\nreturn send_from_directory(f\"static/{group}\", path=filename)\n```\n\nThe `group` sanitization allows dots, so `group=\"..\"` passes validation.  \nThis results in `send_from_directory(\"static/..\", filename)`, effectively shifting the base directory to `/app/changedetectionio` and allowing reads of files in that directory.  \nThe route is unauthenticated, so **any user can retrieve source files** without logging in.\n\n\u003e Limitation: the route only matches `/static/\u003cgroup\u003e/\u003cfilename\u003e` and rejects slashes inside `filename`, so it cannot traverse further to arbitrary system paths like `/etc/passwd`. It is limited to files inside the application package directory.\n\n### PoC\n1) Start an instance (example: Docker on port 5050)\n```\ndocker run -d --name cdio -p 127.0.0.1:5050:5000 -v cdio-data:/datastore cdio-local\n```\n\n2) Reproduce  \n**(URL-encoded traversal)**\n```\ncurl -i http://127.0.0.1:5050/static/%2e%2e/flask_app.py\n```\n\n**(curl path passthrough)**\n```\ncurl --path-as-is -i http://127.0.0.1:5050/static/../flask_app.py\n```\n\n3) Observe that the response body contains Python source code from `flask_app.py`.\n\n### Impact\n- **Vulnerability type:** Directory Traversal / Local File Read\n- **Affected users:** Anyone with network access (no authentication required)\n- **Scope:** Source files under `/app/changedetectionio`\n- **Security impact:** Internal logic exposure can aid further exploitation (Confidentiality: Low)","aliases":["CVE-2026-25527","PYSEC-2026-2124"],"modified":"2026-07-20T19:15:27.590444750Z","published":"2026-07-20T19:06:55Z","database_specific":{"cwe_ids":["CWE-22"],"severity":"MODERATE","github_reviewed":true,"github_reviewed_at":"2026-07-20T19:06:55Z","nvd_published_at":"2026-02-19T15:16:11Z"},"references":[{"type":"WEB","url":"https://github.com/dgtlmoon/changedetection.io/security/advisories/GHSA-9jj8-v89v-xjvw"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-25527"},{"type":"WEB","url":"https://github.com/dgtlmoon/changedetection.io/commit/9d38b4517364831889b5b0d7b3465fd060403fd4"},{"type":"PACKAGE","url":"https://github.com/dgtlmoon/changedetection.io"},{"type":"WEB","url":"https://github.com/pypa/advisory-database/tree/main/vulns/changedetection-io/PYSEC-2026-2124.yaml"}],"affected":[{"package":{"name":"changedetection-io","ecosystem":"PyPI","purl":"pkg:pypi/changedetection-io"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"0.53.2"}]}],"versions":["0.38.2","0.39","0.39.1","0.39.10","0.39.10.post1","0.39.10.post2","0.39.11","0.39.12","0.39.13","0.39.13.1","0.39.14","0.39.14.1","0.39.15","0.39.16","0.39.17","0.39.17.1","0.39.17.2","0.39.18","0.39.19","0.39.19.1","0.39.2","0.39.20","0.39.20.1","0.39.20.2","0.39.20.3","0.39.20.4","0.39.21","0.39.21.1","0.39.22","0.39.22.1","0.39.3","0.39.4","0.39.5","0.39.6","0.39.7","0.39.8","0.39.9","0.40.0","0.40.0.1","0.40.0.2","0.40.0.3","0.40.0.4","0.40.1.0","0.40.1.1","0.40.2","0.40.3","0.41","0.41.1","0.42","0.42.1","0.42.2","0.42.3","0.43.1","0.43.2","0.44","0.44.1","0.45","0.45.1","0.45.11","0.45.12","0.45.13","0.45.14","0.45.15","0.45.16","0.45.17","0.45.18","0.45.19","0.45.2","0.45.20","0.45.21","0.45.22","0.45.23","0.45.24","0.45.25","0.45.26","0.45.3","0.45.4","0.45.5","0.45.6","0.45.7","0.45.7.1","0.45.7.2","0.45.7.3","0.45.8","0.45.8.1","0.45.9","0.46.0","0.46.1","0.46.2","0.46.3","0.46.4","0.47.0","0.47.1","0.47.2","0.47.3","0.47.4","0.47.5","0.47.6","0.48.0","0.48.1","0.48.2","0.48.3","0.48.4","0.48.5","0.48.6","0.49.0","0.49.1","0.49.10","0.49.12","0.49.13","0.49.14","0.49.15","0.49.16","0.49.17","0.49.18","0.49.2","0.49.3","0.49.4","0.49.5","0.49.6","0.49.7","0.49.8","0.49.9","0.50.1","0.50.10","0.50.11","0.50.12","0.50.13","0.50.14","0.50.15","0.50.16","0.50.17","0.50.18","0.50.19","0.50.2","0.50.20","0.50.21","0.50.22","0.50.23","0.50.24","0.50.25","0.50.26","0.50.27","0.50.28","0.50.29","0.50.3","0.50.30","0.50.31","0.50.32","0.50.33","0.50.34","0.50.35","0.50.37","0.50.38","0.50.39","0.50.4","0.50.40","0.50.41","0.50.42","0.50.43","0.50.5","0.50.6","0.50.7","0.50.8","0.50.9","0.51.0","0.51.1","0.51.2","0.51.3","0.51.4","0.52.1","0.52.2","0.52.3","0.52.4","0.52.5","0.52.6","0.52.7","0.52.8","0.52.9","0.53.1"],"database_specific":{"source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/07/GHSA-9jj8-v89v-xjvw/GHSA-9jj8-v89v-xjvw.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N"}]}