Listen to this Post
CVE-2026-73900 is a vulnerability identified in the Helidon product of Oracle Fusion Middleware, specifically within the Imperative Web Server component. The affected version is Helidon 4.5.1. This flaw is categorized as an improper access control issue, mapped to CWE-284. The vulnerability is easily exploitable and allows an unauthenticated attacker with network access via HTTP to compromise the Helidon server. The attack requires no privileges and no user interaction, making it a low-complexity vector for malicious actors.
Upon successful exploitation, an attacker can gain unauthorized read access to a subset of data accessible through Helidon. This could include sensitive configuration details, environment variables, internal service metadata, or other application data that should not be exposed to unauthenticated parties. The vulnerability stems from insufficient access controls within the Imperative Web Server’s request handling logic, where certain endpoints or resources may be accessible without proper authentication or authorization checks.
The CVSS 3.1 base score for this vulnerability is 5.3, which is classified as MEDIUM severity. The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N, indicating a network-accessible attack vector, low attack complexity, no privileges required, no user interaction, and an unchanged scope. The primary impact is on confidentiality, with a low impact rating, while integrity and availability are unaffected. The vulnerability was published on August 18, 2026, and last modified on August 21, 2026. Oracle has released a security advisory addressing this issue, and administrators are advised to apply the necessary patches or mitigations.
DailyCVE Form:
Platform: Oracle Helidon
Version: 4.5.1
Vulnerability: Information Disclosure
Severity: MEDIUM (5.3)
date: 2026-08-18
Prediction: 2026-09-15
What Undercode Say:
The vulnerability exposes a read-only information leak in Helidon’s Imperative Web Server. Attackers can probe the server for accessible endpoints that lack proper authorization. The CVSS score of 5.3 indicates a moderate risk, but the ease of exploitation (network access, no authentication) makes it a prime target for reconnaissance. Organizations should prioritize scanning for Helidon 4.5.1 instances and assess exposure.
Check Helidon version in a running instance
curl -s http://<target>:<port>/health | grep -i "helidon"
Scan for vulnerable endpoints (example)
nmap -p 8080 --script=http-enum <target>
Test for unauthorized access to common Helidon endpoints
curl -s -o /dev/null -w "%{http_code}" http://<target>:<port>/metrics
curl -s -o /dev/null -w "%{http_code}" http://<target>:<port>/openapi
curl -s -o /dev/null -w "%{http_code}" http://<target>:<port>/swagger
Simulate an unauthenticated request to a protected resource
curl -X GET http://<target>:<port>/internal/config -H "Accept: application/json"
Exploit: (Educational Purposes!)
An attacker can exploit this vulnerability by sending crafted HTTP requests to the Helidon Imperative Web Server without any authentication. The server may respond with sensitive data from endpoints that are not properly secured. For example, accessing `/metrics` or `/health` endpoints might reveal internal application state, environment variables, or dependency versions. More critically, unprotected administrative or configuration endpoints could expose database credentials, API keys, or service discovery information. The exploit is trivial to execute using standard tools like `curl` or wget, and does not require specialized skills.
Protection:
- Upgrade Helidon to a patched version as soon as Oracle releases a fix (refer to Oracle Critical Patch Update advisories).
- Restrict network access to Helidon instances using firewalls or security groups, allowing only trusted IP ranges.
- Implement authentication and authorization middleware for all endpoints, especially those exposing sensitive data.
- Disable or restrict access to diagnostic endpoints (
/metrics,/health,/openapi, etc.) in production environments. - Use a Web Application Firewall (WAF) to filter requests to known vulnerable paths.
Impact:
- Unauthorized read access to a subset of Helidon accessible data.
- Exposure of sensitive configuration, environment variables, or internal service metadata.
- Increased attack surface for further reconnaissance and lateral movement within the network.
- Potential compliance violations if exposed data includes personally identifiable information (PII) or regulated data.
- CVSS 3.1 Base Score 5.3 (MEDIUM) with Confidentiality impact rated as LOW.
🎯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
