CVE-2026-43877

AVideo: CSRF in userSavePhoto.php Allows Cross-Origin Overwrite of Authenticated Users' Profile Photos with Arbitrary Content

• Integrity, profile defacement of any logged-in user. One click lets an attacker replace a victim's profile photo with arbitrary bytes: offensive imagery, misleading branding, or a clone of another user's photo for impersonation. The file path is deterministic (photo<users_id>.png), so the attacker can later direct others to the overwritten URL.
• Availability, global cache thrash. Every successful forged request calls clearCache(true), invalidating application-wide caches. Repeatedly tricking logged-in users into visiting the attacker page (e.g., by including the payload as a hidden iframe on a popular site) produces sustained cache invalidation.
• Availability, disk pressure. With no size cap beyond PHP's post_max_size (default 8 MB → ~6 MB after base64 decode), each forged submission writes a multi-megabyte file. Across many victims this enables distributed disk exhaustion.
• No confidentiality impact and no code execution (files are served with Content-Type: image/png based on extension, so SVG-with-script payloads are not interpreted).
• Related endpoints. objects/userSaveBackground.php exhibits the same pattern (same base64DataToImage sink, same lack of CSRF/Origin/MIME checks) and is exploitable identically; fix should be applied consistently.

A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones. Typical impact: state-changing actions performed as the victim without their consent.

CVE-2026-43877 has a CVSS score of 5.4 (Medium). The vector is network-reachable, no privileges required, and user interaction required. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment. No fixed version is listed yet, so configuration controls and monitoring matter more in the interim.

Kodem intelligence

Apply the existing same-origin guard that protects the *.json.php endpoints and add content validation. In objects/userSavePhoto.php, immediately after the login check:

require_once $global['systemRootPath'] . 'objects/functionsSecurity.php';
forbidIfIsUntrustedRequest('userSavePhoto');

$raw = $_POST['imgBase64'] ?? '';
if (strlen($raw) > 2 * 1024 * 1024) { // ~1.5 MB decoded cap
    $obj->msg = __('Image too large');
    die(json_encode($obj));
}
$fileData = base64DataToImage($raw);
if ($fileData === false || $fileData === '' || @imagecreatefromstring($fileData) === false) {
    $obj->msg = __('Invalid image');
    die(json_encode($obj));
}

The longer-term fix is to broaden the global guard in objects/include_config.php so that autoCSRFGuard covers every authenticated POST handler, not only those whose filenames end in .json.php, the current suffix-based gating is a footgun that silently excludes legacy endpoints like userSavePhoto.php and userSaveBackground.php. Also consider moving the clearCache(true) call inside the if ($bytes) branch so that zero-byte writes do not invalidate the global cache.

1. What is CVE-2026-43877? CVE-2026-43877 is a medium-severity cross-site request forgery (CSRF) vulnerability in wwbn/avideo (composer), affecting versions <= 29.0. No fixed version is listed yet. A victim's authenticated browser session is used to submit forged requests to an application that cannot distinguish them from legitimate ones.
2. How severe is CVE-2026-43877? CVE-2026-43877 has a CVSS score of 5.4 (Medium). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
3. Which versions of wwbn/avideo are affected by CVE-2026-43877? wwbn/avideo (composer) versions <= 29.0 is affected.
4. Is there a fix for CVE-2026-43877? No fixed version is listed for CVE-2026-43877 yet. Monitor the advisory for updates and apply mitigations in the interim.
5. Is CVE-2026-43877 exploitable, and should I be worried? Whether CVE-2026-43877 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
6. What actually determines whether CVE-2026-43877 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
7. How do I fix CVE-2026-43877? No fixed version is listed yet. In the interim: Use per-session CSRF tokens on all state-changing operations and verify them server-side. SameSite cookie attributes provide additional defense.

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