CVE-2026-1542: 
WordPress vulnerability analysis and mitigation

CVE-2026-1542 is an unauthenticated PHP Object Injection vulnerability in the Super Stage WP WordPress plugin through version 1.0.1. The plugin unserializes user-supplied input via the REQUEST superglobal without authentication, enabling any remote attacker to inject PHP objects when a suitable gadget chain is present on the target blog. It was publicly disclosed on February 6, 2026, with the CVE published on February 28, 2026, and is fixed in version 1.0.2. It carries a CVSS v3.1 base score of 6.5 (Medium) (WPScan, Feedly).

The root cause is Deserialization of Untrusted Data (CWE-502): the plugin exposes a publicly accessible endpoint at /wp-content/plugins/super-stage-wp/Staging/bridge/bridge.php that accepts a data parameter, base64-decodes it, and passes it directly to PHP's unserialize() function with no authentication or input validation. An attacker crafts a serialized PHP payload, base64-encodes it, and submits it via an unauthenticated HTTP GET or POST request to this endpoint. The actual impact depends on the presence of a suitable PHP gadget chain in the WordPress environment (e.g., from other installed plugins or themes). The vulnerability was discovered and reported by researcher yiğit ibrahim sağlam, and a proof-of-concept confirming the deserialization behavior is publicly available (WPScan).

Successful exploitation can lead to arbitrary PHP object injection, which — when a suitable gadget chain exists in the WordPress installation — may escalate to remote code execution, arbitrary file read/write, or server-side request forgery. The CVSS assessment reflects low confidentiality and integrity impact in the base case, but real-world severity is highly dependent on the gadget chains available from co-installed plugins or themes. No authentication is required, making every publicly accessible WordPress site running the vulnerable plugin a potential target (WPScan, Feedly).

A public proof-of-concept is available via WPScan demonstrating that the vulnerable endpoint is accessible without authentication and that the data parameter is base64-decoded and unserialized. The EPSS score is 0.029% (0.000290), indicating a currently low probability of widespread exploitation. No in-the-wild exploitation, threat actor attribution, or CISA KEV catalog listing has been reported as of the time of this report (WPScan, Feedly).

1. Reconnaissance: Identify WordPress sites running the Super Stage WP plugin (version ≤ 1.0.1) by scanning for the path /wp-content/plugins/super-stage-wp/ using tools like WPScan, Shodan, or Google dorks.
2. Confirm endpoint accessibility: Send a test request to http://TARGET/wp-content/plugins/super-stage-wp/Staging/bridge/bridge.php?data=YToxOntzOjQ6InRlc3QiO3M6NToiaGVsbG8iO30= (base64 of a:1:{s:4:"test";s:5:"hello";}) and verify the response confirms deserialization (e.g., a:1:{s:5:"error";s:21:"could not find action";}).
3. Identify gadget chains: Enumerate other installed plugins and themes on the target to identify known PHP gadget chains (e.g., using tools like PHPGGC) that can be leveraged for code execution or other impacts.
4. Craft malicious payload: Use PHPGGC or a custom gadget chain to generate a serialized PHP object payload targeting an available gadget, then base64-encode it.
5. Deliver payload: Submit the encoded payload via an unauthenticated HTTP request: curl -s "http://TARGET/wp-content/plugins/super-stage-wp/Staging/bridge/bridge.php?data=<BASE64_PAYLOAD>".
6. Achieve objective: Depending on the gadget chain, achieve remote code execution, file write (e.g., web shell upload), or data exfiltration (WPScan).

• Network: Unauthenticated HTTP GET or POST requests to /wp-content/plugins/super-stage-wp/Staging/bridge/bridge.php with a data parameter containing base64-encoded strings; unusual outbound connections from the web server process following such requests.
• Logs: Web server access logs showing requests to bridge.php with base64-encoded data parameters from unexpected or external IP addresses; PHP error logs showing deserialization-related warnings or fatal errors.
• File System: Unexpected new PHP files (web shells) in the WordPress installation directory or plugin folders; modification timestamps on existing files inconsistent with normal update activity.
• Process: Unusual child processes spawned by the web server (e.g., bash, curl, wget, python) following requests to the vulnerable endpoint.

Update the Super Stage WP plugin to version 1.0.2 or later, which addresses the unsafe deserialization of user input. If an immediate update is not possible, consider deactivating or removing the plugin until patching is feasible. Additionally, web application firewall (WAF) rules can be configured to block requests to bridge.php or to detect base64-encoded serialized PHP payloads in request parameters (WPScan).

Wordfence included CVE-2026-1542 in its weekly WordPress vulnerability report for the period of March 2–8, 2026, highlighting it as part of broader plugin security coverage (Wordfence). The vulnerability was also noted by security aggregators including INCIBE-CERT and the ENISA EUVD. No significant independent researcher commentary or viral social media discussion has been identified beyond standard vulnerability disclosure channels.