GHSA-M63R-M9JH-3VC6
Vulnerability from github – Published: 2026-04-14 23:23 – Updated: 2026-04-14 23:23Summary
The directory traversal fix introduced in commit 2375eb5e0 for objects/aVideoEncoderReceiveImage.json.php only checks the URL path component (via parse_url($url, PHP_URL_PATH)) for .. sequences. However, the downstream function try_get_contents_from_local() in objects/functionsFile.php uses explode('/videos/', $url) on the full URL string including the query string. An attacker can place the /videos/../../ traversal payload in the query string to bypass the security check and read arbitrary files from the server filesystem.
Details
The security fix at commit 2375eb5e0 added a traversal check at objects/aVideoEncoderReceiveImage.json.php:49:
$decodedPath = urldecode((string)(parse_url($_REQUEST[$value], PHP_URL_PATH) ?? ''));
if (strpos($decodedPath, '..') !== false) {
unset($_REQUEST[$value]);
}
This only inspects the path component of the URL. For a URL like http://TARGET/x?a=/videos/../../etc/passwd, parse_url() returns /x as the path — no .. is found.
The URL then passes through isValidURL() (objects/functions.php:4203) which accepts it because FILTER_VALIDATE_URL considers .. in query strings valid per RFC 3986.
It also passes isSSRFSafeURL() (objects/functions.php:4264) because the host matches webSiteRootURL, causing an early return at line 4294.
The URL reaches url_get_contents() (objects/functions.php:1938) which calls try_get_contents_from_local() (objects/functionsFile.php:214):
function try_get_contents_from_local($url)
{
// ...
$parts = explode('/videos/', $url);
if (!empty($parts[1])) {
// ...
$tryFile = "{$global['systemRootPath']}{$encoder}videos/{$parts[1]}";
if (file_exists($tryFile)) {
return file_get_contents($tryFile);
}
}
return false;
}
explode('/videos/', $url) operates on the entire URL string including the query string. For the malicious URL, $parts[1] becomes ../../../../../../etc/passwd, constructing a path like /var/www/html/AVideo/Encoder/videos/../../../../../../etc/passwd which PHP's filesystem functions resolve to /etc/passwd.
The file content is returned to the caller and written to the video's thumbnail path via _file_put_contents(). All four downloadURL_* parameters (downloadURL_image, downloadURL_gifimage, downloadURL_webpimage, downloadURL_spectrumimage) are affected.
PoC
Prerequisites: An authenticated AVideo user account with upload permission and an existing video they own (with known videos_id).
-
Identify the AVideo instance's domain (e.g.,
https://avideo.example.com). -
Send a POST request to the ReceiveImage endpoint with the traversal payload in the query string:
curl -s -b "PHPSESSID=<session_cookie>" \
"https://avideo.example.com/objects/aVideoEncoderReceiveImage.json.php" \
-d "videos_id=<YOUR_VIDEO_ID>" \
-d "downloadURL_image=http://avideo.example.com/x?a=/videos/../../../../../../etc/passwd"
-
The response will include
jpgDestSizeindicating the file was read and written (confirming file existence and revealing file size). -
For files that pass image validation (e.g., other users' uploaded images at known paths), the content persists at the video's thumbnail URL and can be retrieved:
curl -s "https://avideo.example.com/videos/<videoFileName>.jpg"
- Non-image files (e.g.,
/etc/passwd, configuration files) are written but then deleted bydeleteInvalidImage(). However, file existence and size are still leaked, and a race condition exists between the write and the deletion.
Impact
- Arbitrary file read: An authenticated user with upload permission can read any file on the server filesystem that the web server process has access to. Files that pass image validation (PNG/JPEG/GIF) are fully exfiltrable via the video thumbnail URL.
- Information disclosure: For non-image files, file existence and size are leaked through the
jpgDestSizeresponse field. - Configuration exposure: Server configuration files, database credentials (
videos/configuration.php), and other sensitive data can be targeted. While PHP files would be deleted bydeleteInvalidImage, there is a race window between write and deletion. - Bypass of security fix: This directly bypasses the path traversal mitigation added in commit 2375eb5e0.
Recommended Fix
The .. check in aVideoEncoderReceiveImage.json.php should inspect the full URL (after URL-decoding), not just the path component. Additionally, try_get_contents_from_local() should validate its derived path.
Fix 1 — Check the full URL in ReceiveImage (objects/aVideoEncoderReceiveImage.json.php:49):
// Replace:
$decodedPath = urldecode((string)(parse_url($_REQUEST[$value], PHP_URL_PATH) ?? ''));
if (strpos($decodedPath, '..') !== false) {
// With:
$decodedFull = urldecode((string)$_REQUEST[$value]);
if (strpos($decodedFull, '..') !== false) {
Fix 2 — Add path validation in try_get_contents_from_local (objects/functionsFile.php:229):
$tryFile = "{$global['systemRootPath']}{$encoder}videos/{$parts[1]}";
// Add traversal check:
$realTryFile = realpath($tryFile);
$videosDir = realpath("{$global['systemRootPath']}{$encoder}videos/");
if ($realTryFile === false || !str_starts_with($realTryFile, $videosDir)) {
return false;
}
if (file_exists($tryFile)) {
return file_get_contents($tryFile);
}
{
"affected": [
{
"package": {
"ecosystem": "Packagist",
"name": "wwbn/avideo"
},
"ranges": [
{
"events": [
{
"introduced": "0"
},
{
"last_affected": "29.0"
}
],
"type": "ECOSYSTEM"
}
]
}
],
"aliases": [],
"database_specific": {
"cwe_ids": [
"CWE-22"
],
"github_reviewed": true,
"github_reviewed_at": "2026-04-14T23:23:14Z",
"nvd_published_at": null,
"severity": "MODERATE"
},
"details": "## Summary\n\nThe directory traversal fix introduced in commit 2375eb5e0 for `objects/aVideoEncoderReceiveImage.json.php` only checks the URL **path component** (via `parse_url($url, PHP_URL_PATH)`) for `..` sequences. However, the downstream function `try_get_contents_from_local()` in `objects/functionsFile.php` uses `explode(\u0027/videos/\u0027, $url)` on the **full URL string** including the query string. An attacker can place the `/videos/../../` traversal payload in the query string to bypass the security check and read arbitrary files from the server filesystem.\n\n## Details\n\nThe security fix at commit 2375eb5e0 added a traversal check at `objects/aVideoEncoderReceiveImage.json.php:49`:\n\n```php\n$decodedPath = urldecode((string)(parse_url($_REQUEST[$value], PHP_URL_PATH) ?? \u0027\u0027));\nif (strpos($decodedPath, \u0027..\u0027) !== false) {\n unset($_REQUEST[$value]);\n}\n```\n\nThis only inspects the **path component** of the URL. For a URL like `http://TARGET/x?a=/videos/../../etc/passwd`, `parse_url()` returns `/x` as the path \u2014 no `..` is found.\n\nThe URL then passes through `isValidURL()` (`objects/functions.php:4203`) which accepts it because `FILTER_VALIDATE_URL` considers `..` in query strings valid per RFC 3986.\n\nIt also passes `isSSRFSafeURL()` (`objects/functions.php:4264`) because the host matches `webSiteRootURL`, causing an early return at line 4294.\n\nThe URL reaches `url_get_contents()` (`objects/functions.php:1938`) which calls `try_get_contents_from_local()` (`objects/functionsFile.php:214`):\n\n```php\nfunction try_get_contents_from_local($url)\n{\n // ...\n $parts = explode(\u0027/videos/\u0027, $url);\n if (!empty($parts[1])) {\n // ...\n $tryFile = \"{$global[\u0027systemRootPath\u0027]}{$encoder}videos/{$parts[1]}\";\n if (file_exists($tryFile)) {\n return file_get_contents($tryFile);\n }\n }\n return false;\n}\n```\n\n`explode(\u0027/videos/\u0027, $url)` operates on the **entire URL string** including the query string. For the malicious URL, `$parts[1]` becomes `../../../../../../etc/passwd`, constructing a path like `/var/www/html/AVideo/Encoder/videos/../../../../../../etc/passwd` which PHP\u0027s filesystem functions resolve to `/etc/passwd`.\n\nThe file content is returned to the caller and written to the video\u0027s thumbnail path via `_file_put_contents()`. All four `downloadURL_*` parameters (`downloadURL_image`, `downloadURL_gifimage`, `downloadURL_webpimage`, `downloadURL_spectrumimage`) are affected.\n\n## PoC\n\nPrerequisites: An authenticated AVideo user account with upload permission and an existing video they own (with known `videos_id`).\n\n1. Identify the AVideo instance\u0027s domain (e.g., `https://avideo.example.com`).\n\n2. Send a POST request to the ReceiveImage endpoint with the traversal payload in the query string:\n\n```bash\ncurl -s -b \"PHPSESSID=\u003csession_cookie\u003e\" \\\n \"https://avideo.example.com/objects/aVideoEncoderReceiveImage.json.php\" \\\n -d \"videos_id=\u003cYOUR_VIDEO_ID\u003e\" \\\n -d \"downloadURL_image=http://avideo.example.com/x?a=/videos/../../../../../../etc/passwd\"\n```\n\n3. The response will include `jpgDestSize` indicating the file was read and written (confirming file existence and revealing file size).\n\n4. For files that pass image validation (e.g., other users\u0027 uploaded images at known paths), the content persists at the video\u0027s thumbnail URL and can be retrieved:\n\n```bash\ncurl -s \"https://avideo.example.com/videos/\u003cvideoFileName\u003e.jpg\"\n```\n\n5. Non-image files (e.g., `/etc/passwd`, configuration files) are written but then deleted by `deleteInvalidImage()`. However, file existence and size are still leaked, and a race condition exists between the write and the deletion.\n\n## Impact\n\n- **Arbitrary file read**: An authenticated user with upload permission can read any file on the server filesystem that the web server process has access to. Files that pass image validation (PNG/JPEG/GIF) are fully exfiltrable via the video thumbnail URL.\n- **Information disclosure**: For non-image files, file existence and size are leaked through the `jpgDestSize` response field.\n- **Configuration exposure**: Server configuration files, database credentials (`videos/configuration.php`), and other sensitive data can be targeted. While PHP files would be deleted by `deleteInvalidImage`, there is a race window between write and deletion.\n- **Bypass of security fix**: This directly bypasses the path traversal mitigation added in commit 2375eb5e0.\n\n## Recommended Fix\n\nThe `..` check in `aVideoEncoderReceiveImage.json.php` should inspect the **full URL** (after URL-decoding), not just the path component. Additionally, `try_get_contents_from_local()` should validate its derived path.\n\n**Fix 1 \u2014 Check the full URL in ReceiveImage (objects/aVideoEncoderReceiveImage.json.php:49):**\n\n```php\n// Replace:\n$decodedPath = urldecode((string)(parse_url($_REQUEST[$value], PHP_URL_PATH) ?? \u0027\u0027));\nif (strpos($decodedPath, \u0027..\u0027) !== false) {\n\n// With:\n$decodedFull = urldecode((string)$_REQUEST[$value]);\nif (strpos($decodedFull, \u0027..\u0027) !== false) {\n```\n\n**Fix 2 \u2014 Add path validation in try_get_contents_from_local (objects/functionsFile.php:229):**\n\n```php\n$tryFile = \"{$global[\u0027systemRootPath\u0027]}{$encoder}videos/{$parts[1]}\";\n// Add traversal check:\n$realTryFile = realpath($tryFile);\n$videosDir = realpath(\"{$global[\u0027systemRootPath\u0027]}{$encoder}videos/\");\nif ($realTryFile === false || !str_starts_with($realTryFile, $videosDir)) {\n return false;\n}\nif (file_exists($tryFile)) {\n return file_get_contents($tryFile);\n}\n```",
"id": "GHSA-m63r-m9jh-3vc6",
"modified": "2026-04-14T23:23:14Z",
"published": "2026-04-14T23:23:14Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/WWBN/AVideo/security/advisories/GHSA-m63r-m9jh-3vc6"
},
{
"type": "WEB",
"url": "https://github.com/WWBN/AVideo/commit/bd11c16ec894698e54e2cdae25026c61ad1ed441"
},
{
"type": "PACKAGE",
"url": "https://github.com/WWBN/AVideo"
}
],
"schema_version": "1.4.0",
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N",
"type": "CVSS_V3"
}
],
"summary": "WWBN AVideo has an Incomplete fix: Directory traversal bypass via query string in ReceiveImage downloadURL parameters"
}
Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.