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CVE-2026-21962 is a critical vulnerability affecting the Oracle HTTP Server and the Oracle WebLogic Server Proxy Plug-in components of Oracle Fusion Middleware. The flaw resides in the request handling logic of the WebLogic Server Proxy Plug-in, which is used with both Apache HTTP Server and Microsoft IIS. Due to improper parsing and forwarding of specially crafted or encoded HTTP request paths, the proxy may unintentionally expose internal backend resources. An unauthenticated attacker with network access via HTTP can exploit this vulnerability without any user interaction. Successful exploitation allows the attacker to bypass security controls and gain unauthorized access to backend WebLogic systems, potentially leading to unauthorized creation, deletion, or modification of critical data. The vulnerability has a CVSS v3.1 base score of 10.0 (Critical), with the vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N. It is easily exploitable with low attack complexity and a scope change impact. Active exploitation has been observed worldwide, with attackers utilizing automated scanning and exploit attempts. Attackers are leveraging path traversal techniques and exploiting the ProxyServlet component. The affected supported versions are 12.2.1.4.0, 14.1.1.0.0, and 14.1.2.0.0. For the WebLogic Server Proxy Plug-in for IIS, only version 12.2.1.4.0 is affected. Oracle released fixes for this vulnerability in its January 2026 Critical Patch Update.
DailyCVE Form:
Platform: Oracle Fusion Middleware
Version: 12.2.1.4.0, 14.1.1.0.0, 14.1.2.0.0
Vulnerability: Authentication Bypass
Severity: CRITICAL (CVSS 10.0)
Date: January 20, 2026
Prediction: Patch already available (Jan 2026 CPU)
What Undercode Say:
The following bash commands and codes can be used to check for the presence of the vulnerability and to analyze potential exploitation attempts:
Check affected versions of Oracle HTTP Server / WebLogic Proxy Plug-in Run on the server hosting the Oracle HTTP Server or WebLogic Proxy grep -r "WebLogic" /path/to/installation Check for suspicious log entries indicating exploitation attempts Look for unusual /weblogic/ or encoded path requests in access logs grep -E "(/weblogic/|%2e%2e%2f|../)" /path/to/access_log Check for unauthorized changes or unexpected processes Review system logs for unusual activity sudo tail -f /var/log/syslog | grep -i "weblogic" Example of a crafted HTTP request that could be used to test for the vulnerability (This is for detection purposes only, not exploitation) curl -k "https://target-server/weblogic/../../../../etc/passwd"
Analytics:
- Active Exploitation: Observed worldwide with automated scanning
- Attack Techniques: Path traversal and ProxyServlet exploitation
- Attack Vector: Remote, unauthenticated HTTP-based
- Impact: Unauthorized read/write access to sensitive data
Exploit: (Educational Purposes!)
The exploitation of CVE-2026-21962 typically involves sending specially crafted HTTP requests to the affected proxy plug-in. The attack leverages improper handling of encoded path traversal sequences to bypass access controls and access internal backend resources. Below is a conceptual example for educational purposes only:
Educational example of a potential exploit vector This demonstrates the path traversal technique used by attackers curl -k "https://vulnerable-server/weblogic/..%252f..%252f..%252f..%252fetc/passwd" Another example using double URL encoding to bypass filters curl -k "https://vulnerable-server/%2e%2e%2f%2e%2e%2f%2e%2e%2f%2e%2e%2fetc/passwd"
Note: These commands are for educational and defensive purposes only. Unauthorized exploitation of this vulnerability is illegal and unethical.
Protection:
- Apply Patches Immediately: Apply Oracle’s January 2026 Critical Patch Update (CPU) for all affected components. This is the only complete remediation.
- Restrict Network Access: Limit external and untrusted access to affected Oracle HTTP Server and WebLogic Proxy instances. Allow only trusted IP addresses to connect.
- Deploy WAF Rules: Deploy and tune Web Application Firewall (WAF) rules to detect and block known path-traversal and ProxyServlet exploit patterns.
- Monitor Logs: Monitor access logs for suspicious requests containing `/weblogic/` or encoded path traversal sequences (e.g.,
%2e%2e%2f,..%252f). - Do Not Expose Admin Consoles: Do not expose WebLogic admin consoles or proxy endpoints to the public internet; restrict access via VPN, bastion, or firewall allowlists.
Impact:
- Confidentiality: Unauthorized access to critical data or complete access to all Oracle HTTP Server / WebLogic Proxy Plug-in accessible data
- Integrity: Unauthorized creation, deletion, or modification of critical data
- Availability: No direct availability impact (CVSS score A:N)
- Scope: Scope change – attacks may significantly impact additional products
- Business Impact: Potential pivoting into backend WebLogic clusters, exposing infrastructure traditionally trusted as a secure gateway
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Sources:
Reported By: www.cve.org
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