Dmitry VerkhoturovandUmputun
59c92f8c4d
The unauthenticated GET /api/v1/picture/{user}/{id} handler concatenated the
two URL params verbatim into a filesystem path via path.Join, so a request
like /api/v1/picture/../remark.db resolved to <base>/../remark.db, escaping
the image directory. With Partitions=0 (a documented option) this is a
direct arbitrary-file read; with the default Partitions=100 the constructed
path lands in a CRC-derived subdirectory but the server still leaks the
internal filesystem path back to the unauthenticated caller via the JSON
error body — confirmed against demo.remark42.com (master-80c12a3) which
returned `stat /var/folders/.../staging/.../remark.db` for `..` requests.
Validate both URL segments via safePictureSegment (no traversal markers,
no path separators, no NULs) at the handler entry, and replace the raw
storage error with a generic "image not found" response. The original
error is logged for operators.
Reproduction test asserts that ../remark.db, foo/..%2Fremark.db and
%2E%2E/remark.db all return 400 with no internal path leaked.
Remark42 
Remark42 is a self-hosted, lightweight and simple (yet functional) comment engine, which doesn't spy on users. It can be embedded into blogs, articles, or any other place where readers add comments.
- Social login via Google, Facebook, Microsoft, GitHub, Apple, Yandex, Patreon, Discord, Telegram and custom OAuth2 providers
- Login via email
- Optional anonymous access
- Multi-level nested comments with both tree and plain presentations
- Import from Disqus and WordPress
- Markdown support with friendly formatter toolbar
- Moderator can remove comments and block users
- Voting, pinning and verification system
- Sortable comments
- Images upload with drag-and-drop
- Extractor for recent comments, cross-post
- RSS for all comments and each post
- Telegram, Slack, Webhook and email notifications for Admins (get notified for each new comment)
- Email and Telegram notifications for users (get notified when someone responds to your comment)
- Export data to JSON with automatic backups
- No external databases, everything embedded in a single data file
- Fully dockerized and can be deployed in a single command
- Self-contained executable can be deployed directly to Linux, Windows and macOS
- Clean, lightweight and customizable UI with white and dark themes
- Multi-site mode from a single instance
- Integration with automatic SSL (direct and via nginx-le)
- Privacy focused
Demo site available with all authentication methods, including email auth and anonymous access.
All remark42 documentation is available by the link.
Contribution
In order to start and work on the project locally in development mode check our contribution documentation for backend and frontend.
If you are interested in adding a new localization please check these docs.