{"id":"GHSA-65mp-fq8v-56jr","aliases":["CVE-2026-27641","PYSEC-2026-341"],"title":"Flask-Reuploaded vulnerable to Remote Code Execution via Server-Side Template Injection","description":"### Impact\nA critical path traversal and extension bypass vulnerability in Flask-Reuploaded allows remote attackers to achieve arbitrary file write and remote code execution through Server-Side Template Injection (SSTI).\n\n### Patches\nFlask-Reuploaded has been patched in version 1.5.0\n\n### Workarounds\n\n1. **Do not pass user input to the `name` parameter**\n2. Use auto-generated filenames only\n3. Implement strict input validation if `name` must be used\n\n```python\nfrom werkzeug.utils import secure_filename\nimport os\n\n# Sanitize user input before passing to save()\nsafe_name = secure_filename(request.form.get('custom_name'))\n# Remove path separators\nsafe_name = os.path.basename(safe_name)\n# Validate extension matches policy\nif not photos.extension_allowed(photos.get_extension(safe_name)):\n    abort(400)\n    \nfilename = photos.save(file, name=safe_name)\n```\n\n### Resources\nThe fix is documented in the pull request, see https://github.com/jugmac00/flask-reuploaded/pull/180.\n\nA proper write-up was created by the reporter of the vulnerability, Jaron Cabral (https://www.linkedin.com/in/jaron-cabral-751994357/), but is not yet available as of time of this publication.","severity":"critical","score":9.8,"published":"2026-02-25T19:06:50.000Z","modified":"2026-10-27T17:00:03.992Z","withdrawn":false,"knownExploited":false,"affected":[{"ecosystem":"PyPI","name":"flask-reuploaded","ranges":[{"events":[{"introduced":"0"},{"fixed":"1.5.0"}],"type":"ECOSYSTEM"}],"versions":["0.3","0.3.1","0.3.2","0.4.0","0.5.0","1.0.0","1.1.0","1.2.0","1.3.0","1.4.0"],"fixed":["1.5.0"]}],"references":["https://github.com/jugmac00/flask-reuploaded/security/advisories/GHSA-65mp-fq8v-56jr","https://nvd.nist.gov/vuln/detail/CVE-2026-27641","https://github.com/jugmac00/flask-reuploaded/pull/180","https://github.com/jugmac00/flask-reuploaded/commit/d64c6b2f71cb73734fc38baa0e3e156926361288","https://github.com/jugmac00/flask-reuploaded","https://github.com/pypa/advisory-database/tree/main/vulns/flask-reuploaded/PYSEC-2026-341.yaml","https://pypi.org/project/flask-reuploaded"],"sources":[{"name":"OSV","id":"GHSA-65mp-fq8v-56jr","modified":"2026-10-27T17:00:03.992051129Z","url":"https://osv.dev/vulnerability/GHSA-65mp-fq8v-56jr"}],"assessments":[{"source":"OSV","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","score":9.8}]}