Listen to this Post
CVE-2026-73899 is a vulnerability in the Helidon product of Oracle Fusion Middleware, specifically within the Imperative Web Server component. Helidon is a Java-based microservices framework designed for building cloud-native applications, and the Imperative Web Server is its traditional, blocking web server implementation.
The vulnerability stems from an Improper Access Control (CWE-284) flaw. In affected versions, the Imperative Web Server fails to properly enforce authorization checks on certain HTTP requests. An unauthenticated attacker with network access can send crafted HTTP requests to the server. Because the server does not adequately validate the requester’s permissions, it responds with data that should have been restricted.
The vulnerability is easily exploitable—it requires no authentication, no user interaction, and can be triggered remotely over the network. The attacker does not need any special privileges or prior access. A successful exploit results in unauthorized read access to a subset of Helidon-accessible data. This could include sensitive information such as configuration files, environment variables, or other data exposed by the Helidon server.
The CVSS 3.1 Base Score is 5.3 (Medium) with the vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N. The attack complexity is low, and the confidentiality impact is limited (Low), with no impact on integrity or availability. The vulnerability is specific to Helidon version 3.2.19. Oracle has addressed the issue in version 3.2.20 or later.
DailyCVE Form:
Platform: Oracle Helidon
Version: 3.2.19
Vulnerability: Information Disclosure
Severity: Medium (5.3)
Date: 2026-08-18
Prediction: Patch already available (3.2.20)
What Undercode Say:
Analytics:
- CVSS Score: 5.3 (Medium)
- EPSS Score: 0.32% (low likelihood of exploitation)
- Public PoC: None confirmed
- Weaponized Exploit: Unknown
- Internet-Facing Risk: Medium
- Internal-Only Risk: Low
Exploit: (Educational Purposes!)
Check Helidon version java -jar helidon.jar --version Example curl request that may trigger the vulnerability (This is a conceptual example - actual exploit details are not public) curl -X GET http://target-helidon-server:8080/sensitive/endpoint Potential attack pattern: accessing restricted paths curl -X GET http://target-helidon-server:8080/../config/application.yaml Network reconnaissance for vulnerable instances nmap -p 8080 --open target-network -oG helidon_scan.txt
Protection:
Option 1: Apply the official patch - upgrade to Helidon 3.2.20 or later
Download the latest version from Oracle repository
Replace existing Helidon libraries and restart the server
Option 2: Restrict network access using iptables
iptables -A INPUT -p tcp --dport 8080 -s <trusted_ip> -j ACCEPT
iptables -A INPUT -p tcp --dport 8080 -j DROP
Option 3: Use a reverse proxy to filter requests
nginx configuration example
location / {
proxy_pass http://helidon-backend:8080;
Add request filtering and logging
}
Option 4: Deploy a Web Application Firewall (WAF)
Option 5: Monitor logs for suspicious activity
tail -f /var/log/helidon/access.log | grep -E "(/etc/|/proc/|/../)"
Impact:
- Data Exposure: Unauthorized read access to Helidon-accessible data, including configuration files, environment variables, and potentially sensitive application data
- Intelligence Gathering: Attackers can use disclosed information to plan more targeted attacks
- Compliance Risks: Exposure of sensitive data may lead to regulatory violations (GDPR, HIPAA, etc.)
- Reputational Damage: Data breaches can erode customer trust and brand reputation
- Lateral Movement: Obtained credentials or configuration details could enable further compromise of internal systems
- No Integrity or Availability Impact: The vulnerability does not allow data modification or service disruption
🎯Let’s Practice Exploiting & Learn Patching For Free:
🎓 Live Courses & Certifications:
Join Undercode Academy for Verified Certifications
🚀 Request a Custom Project:
Secure, high-velocity infrastructure and disruptive technological engineering. Contact our engineering team for high-tier development and proprietary systems:
[email protected]
💎 Smart Architecture | 🛡️ Secure by Design | ⭐ Trusted by Thousands
Sources:
Reported By: nvd.nist.gov
Extra Source Hub:
Undercode
