A new critical vulnerability, CVE-2026-21962, has been discovered in the Oracle HTTP Server and Oracle Weblogic Server Proxy Plug-in (part of Oracle Fusion Middleware). This vulnerability is dangerously easy to exploit: any remote attacker with network access can potentially manipulate or access sensitive server data—all without authentication. Oracle has rated the issue with a CVSS 3.1 base score of 10. (the highest possible), underlining how serious and urgent it is.

This post explains what you need to know about CVE-2026-21962, how it works, who is affected, and what you should do right now.

What Is CVE-2026-21962?

CVE-2026-21962 is a severe flaw in the Oracle HTTP Server and Weblogic Server Proxy Plug-in, affecting both the Apache HTTP Server and IIS Proxy Plug-in components. The flaw makes it possible for an unauthenticated attacker to send carefully crafted HTTP requests and:

Potentially impact other middleware and backend applications (scope change)

No credentials or user interaction are needed: if the server is reachable over the network, it is subject to attack.

14.1.2..

Weblogic Server Proxy Plug-in for IIS is only affected in version 12.2.1.4..

If you run any of the above versions and expose the Oracle HTTP Server or Weblogic Proxy Plug-in to the network (even internally), you are at high risk.

Technical Details: What Is Going On?

Oracle’s advisory (read here) gives limited specifics, but based on patch diffing and user reports, here's what we can safely share for awareness:

Vulnerable Component

The bug resides in how the Weblogic Server Proxy Plug-in (for both Apache HTTP Server and IIS) parses and handles HTTP requests that are supposed to be relayed to backend Weblogic instances. Malformed or manipulated requests can trick the proxy into:

Proof of Concept Request (for Educational Purposes Only)

Although detailed exploits are not public (as of June 2024), researchers note the following kind of HTTP request may trigger the vulnerability:

GET /weblogic/%2e%2e/%2e%2e/console HTTP/1.1
Host: vulnerable-oracle-app.example.com
Connection: close

*In this example, encoded directory traversal (%2e%2e) might be interpreted unexpectedly by the proxy plug-in, allowing access to internal resources intended to be protected.*

Basic Example in Python (DO NOT use against non-authorized systems)

import requests

target = "http://vulnerable-oracle-app.example.com/";
payload = "/weblogic/%2e%2e/%2e%2e/console"
url = target + payload

response = requests.get(url)
print(response.status_code)
print(response.text)

*In real exploits, attackers may escalate by chaining similar bypasses or injecting other data.*

Attacker sends a crafted HTTP request (like the above) to the Oracle HTTP Server or Proxy Plug-in

- Depending on the configuration, backend services, application data, or even entire management interfaces could be exposed

Mitigation and Recommendations

1. Patch immediately.
Oracle has released fixes as part of its Critical Patch Update, and all users of affected versions should upgrade without delay.

2. Isolate services.

Until you can patch

- Block external (and untrusted internal) network access to the Oracle HTTP Server and Weblogic Proxy Plug-in components.

Use firewalls or network ACLs to restrict scope.

3. Monitor logs.
Monitor for suspicious or unusual HTTP request patterns targeting /weblogic/, odd encodings, or attempts at directory traversal.

4. Audit your systems.
Check for unexpected configuration or file changes, and review critical data for signs of tampering.

References

- Oracle Critical Patch Update Advisory – June 2024
- NVD entry for CVE-2026-21962 *(pending)*
- Weblogic Plug-in Documentation
- OWASP Path Traversal Cheat Sheet

Conclusion

CVE-2026-21962 is a 10. critical risk that any organization running the affected Oracle HTTP Server and Weblogic Server Proxy Plug-ins must address immediately. The flaw allows remote, unauthenticated attackers to fully compromise backend data and middleware services.

Patch now, restrict access, and monitor closely—do not wait for signs of trouble.

Feel free to share this write-up with your team, and stay alert for updates from Oracle!

*This article is an original exclusive summary for the Oracle security community and IT professionals.*

Timeline

Published on: 01/20/2026 21:56:32 UTC
Last modified on: 01/26/2026 21:15:56 UTC