Summary
FromHEIC processes your files in your browser, inside a Web Worker, with no server-side component. That lowers some risks, and it does not remove all of them. Nothing is “100% safe”, and we do not claim it.
What the browser gives us
- The sandbox. Web pages run in a restricted environment. A page cannot freely read your disk. It only gets the files you choose.
- No upload path by design. The tools have no server component, so there is no place on our side where your file lands.
- Content-Security-Policy (CSP). The site sends a CSP that limits network connections to its own origin and Google Analytics, which loads only if you accept it. If a script on the page tried to send your photo to any other domain, the browser would block that connection.
- Same-origin codecs. Decoders and encoders are WebAssembly files served from this domain, loaded only when needed.
- Web Worker. Heavy decoding runs in a worker, separate from the page’s interface.
The risk that remains: codecs
Image parsers have had real vulnerabilities. For example, CVE-2023-41064 is a published CVE record for image-handling software. The record page needs JavaScript, so read it there for the affected product and details. We cite it as proof that parsing untrusted images is a known source of bugs, not to say anything about FromHEIC specifically.
FromHEIC uses open-source libraries (libheif, libde265, libwebp, libavif/aom). A malicious or damaged file could trigger a bug in them. The WebAssembly sandbox and the browser’s own protections are meant to contain such a bug inside the tab, but a browser bug could still matter. Keep your browser up to date.
Practical limits
- Limits of 200 MB per file, 100 megapixels per image and 200 files per batch reduce the chance of runaway memory use, but do not eliminate it.
- File types are identified from contents, and outputs are re-parsed before download. That checks structure, not intent.
- Metadata removal covers standard EXIF, XMP and GPS fields that the tool reads. It is not a guarantee that a photo is anonymous. The picture itself can reveal things.
- A map link in the metadata viewer opens an external site (OpenStreetMap) only after you press a button.
- The site cannot protect a device that is already compromised, or files you share onward.
Habits we recommend
- Keep your browser and operating system updated.
- Be careful with files from unknown senders. See the guide on image file safety.
- Use the file checker and health check to inspect odd files before converting.
- Keep your originals.
- Remove location data before posting photos.
Reporting a vulnerability
Email contact@gohammer.mobi with the page, your browser and steps to reproduce. Avoid publishing details until the owner has had a chance to respond. The operator is Hammer Desenvolvimento de Software.