Cloudanix VulnDB

CVE-2026-91453

Medium · 5.3

CVSS

5.3

EPSS

0.3%

Published

Oct 20, 2026

CISA due date

—

Cloudanix analysis

Monitor only SSVC: Track

A problem in certain Oracle Java software lets network attackers change some data inside applications without needing any login or special access.

Exploitation
Remote Unauthenticated
Attacker needs
None
Complexity
Low
Impact
Data Tampering
Component
Network Service
Class
Authorization Bypass
Remediation
Upgrade
Effort
Medium
Patch risk
Low

What it actually does

The Lightweight HTTP Server component fails to enforce authorization checks on API endpoints, allowing unauthenticated callers to perform update, insert, or delete operations on accessible data.

Why it matters to the business

Attackers can alter data handled by Java applications that expose the Lightweight HTTP Server, potentially causing integrity violations with minimal attacker effort and no prior access required.

How an attack unfolds

An unauthenticated attacker locates a network-reachable Lightweight HTTP Server instance and supplies crafted data directly to its APIs over supported protocols, bypassing intended authorization to modify stored data.

How to fix it

Apply the latest Oracle Critical Patch Update that addresses this issue in the Lightweight HTTP Server component for all affected Java SE, GraalVM for JDK, and GraalVM Enterprise Edition releases.

How to confirm the fix worked

Confirm deployment of patched Java runtimes, review application configurations to ensure the Lightweight HTTP Server is not exposed without additional controls, and test that API requests now require proper authorization.

Typical attack path

  1. Scan for exposed Lightweight HTTP Server ports or endpoints
  2. Craft and send unauthenticated requests containing data payloads to component APIs
  3. Observe successful modification of target data without authentication or trusted applet context

How to detect it

Review web server or application logs for unauthenticated requests that result in data modification actions on endpoints served by the Lightweight HTTP Server; look for patterns of successful write operations from unexpected sources shortly after publication.

What your security team should do

  • Prioritize patching Java installations within standard maintenance windows given low exploit maturity and EPSS
  • Restrict network exposure of the Lightweight HTTP Server to trusted sources only
  • Monitor Oracle CPU releases for the exact fixed versions once published

The record

Vulnerability in the Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition product of Oracle Java SE (component: Lightweight HTTP Server). Supported versions that are affected are Oracle Java SE: 8u503, 8u503-perf, 11.0.32.1, 17.0.20.1, 21.0.12.1, 25.0.4.1, 27; Oracle GraalVM for JDK: 17.0.20.1 and 21.0.12.1; Oracle GraalVM Enterprise Edition: 21.3.19.1.1. Easily exploitable vulnerability allows unauthenticated attacker with network access via multiple protocols to compromise Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition. Successful attacks of this vulnerability can result in unauthorized update, insert or delete access to some of Oracle Java SE, Oracle GraalVM for JDK, Oracle GraalVM Enterprise Edition accessible data. Note: This vulnerability can only be exploited by supplying data to APIs in the specified Component without using Untrusted Java Web Start applications or Untrusted Java applets, such as through a web service. CVSS 3.1 Base Score 5.3 (Integrity impacts). CVSS Vector: (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N).

Affected packages

Ecosystem Package Introduced Fixed

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