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CVE-2026-73893 is a vulnerability identified in Oracle Helidon, specifically within its Imperative Web Server component. Helidon is an open-source, lightweight microservices framework developed by Oracle. The vulnerability affects version 4.5.0 of the framework and is categorized under CWE-284 (Improper Access Control). This indicates a failure in the product’s access control mechanisms, potentially allowing unauthorized operations.
The core of the issue lies in how the Imperative Web Server handles privileges and access requests. An attacker can exploit this flaw without needing any authentication. The attack vector is network-based, utilizing the HTTP protocol. The vulnerability is considered easily exploitable due to its low attack complexity and the lack of required privileges or user interaction.
A successful exploit can lead to two primary impacts. First, an attacker could gain unauthorized read access to a subset of data accessible to the Helidon server. Second, and more severely, they could perform unauthorized update, insert, or delete operations on some of that data. This means an attacker could not only view sensitive information but also potentially corrupt or manipulate application data.
The vulnerability has been assigned a CVSS v3.1 base score of 6.5, which is considered MEDIUM in severity. The CVSS vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N, confirming the network attack vector, low complexity, and lack of authentication requirements, resulting in limited but tangible impacts on confidentiality and integrity.
Public disclosure of the CVE occurred around August 18, 2026. As of now, there is no known public proof-of-concept (PoC) exploit available. However, the ease of exploitation makes it a significant risk for any organization using the affected version, especially if the Helidon server is exposed to the internet. The vulnerability is classified as critical by some sources due to the potential for data compromise, with exploit prices estimated in the range of $5,000 to $25,000.
DailyCVE Form:
Platform: Oracle Helidon
Version: 4.5.0
Vulnerability: Improper Access Control
Severity: 6.5 MEDIUM
date: 08/18/2026
Prediction: 08/19/2026
What Undercode Say:
Analytics from security advisories indicate that while a public exploit is not yet available, the vulnerability’s low complexity and network accessibility make it a prime target for attackers. The primary risk is for internet-facing instances of Helidon 4.5.0. Organizations should prioritize patching and implementing network controls.
To check if your system is vulnerable, you can verify the Helidon version:
java -jar helidon.jar --version
This command should output the version. If it is 4.5.0, the system is vulnerable.
Exploit: (Educational Purposes!)
As no public exploit code is available, the exploitation process is theoretical. An unauthenticated attacker would send crafted HTTP requests to the vulnerable Helidon Imperative Web Server. The goal is to manipulate the server’s access control logic to perform unauthorized data operations.
A basic example of a potential malicious request could look like:
curl -X GET http://<target-helidon-server>:<port>/sensitive/data
Or to modify data:
curl -X POST http://<target-helidon-server>:<port>/api/data -d '{"malicious":"payload"}'
The success of these requests would depend on the specific vulnerable endpoints within the application.
Protection:
The official fix for this vulnerability is to upgrade to Helidon version 4.5.1 or later. This patch should be applied immediately to mitigate the risk.
As a temporary workaround until patching is possible, restrict network access to the Helidon server. Use firewall rules to allow connections only from trusted networks:
iptables -A INPUT -p tcp --dport <port> -s <trusted_network> -j ACCEPT iptables -A INPUT -p tcp --dport <port> -j DROP
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Impact:
Successful exploitation allows an attacker to:
- Read sensitive data accessible to the Helidon server without authorization.
- Modify, insert, or delete application data, potentially leading to data corruption or manipulation.
- Compromise the confidentiality and integrity of the application, which could result in data breaches or significant business disruption.
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Sources:
Reported By: nvd.nist.gov
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