CVE-2026-18527: Software Security Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-rg54-x42p-hp27
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CVSS 9.9
CWE-384
Published
Advisory Summary

CVE-2026-18527 is a CRITICAL (CVSS 9.9) security vulnerability vulnerability (CWE-384: Session Fixation) affecting Software libraries in the Maven ecosystem. The weakness occurs when authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-18527 at a Glance

CVE Identifier CVE-2026-18527
GHSA Identifier GHSA-rg54-x42p-hp27
Severity CRITICAL
CVSS v3.1 Base Score 9.9
CWE Classification CWE-384: Session Fixation
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.9

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Changed (S:C)
Confidentiality High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2026-18527

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-18527, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-384: Session Fixation, where authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

IBM Administration Runtime Expert for i 1R1M0 IBM Application Runtime Expert (ARE) for i could allow a remote attacker to gain elevated privileges, caused by ARE GUI component processing. An unauthenticated attacker can exploit this vulnerability to execute actions under another user's authenticated profile gaining elevated privileges on the IBM i system.

References

NVD — CVE-2026-18527 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-18527
www.ibm.com/support/pages/node/... WEB
https://www.ibm.com/support/pages/node/7284580

Frequently Asked Questions

What is CVE-2026-18527?
CVE-2026-18527 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-384: Session Fixation.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-18527?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-18527?
CVE-2026-18527 has a CVSS v3.1 base score of 9.9 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
What CWE is associated with CVE-2026-18527?
CVE-2026-18527 is classified under CWE-384: Session Fixation (Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.).
How can I check Maven dependencies for CVE-2026-18527?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-rg54-x42p-hp27",
  "modified" : "2026-08-29T00:31:01Z",
  "published" : "2026-08-29T00:31:01Z",
  "aliases" : [ "CVE-2026-18527" ],
  "details" : "IBM Administration Runtime Expert for i 1R1M0 IBM Application Runtime Expert (ARE) for i could allow a remote attacker to gain elevated privileges, caused by ARE GUI component processing. An unauthenticated attacker can exploit this vulnerability to execute actions under another user's authenticated profile gaining elevated privileges on the IBM i system.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-18527"
  }, {
    "type" : "WEB",
    "url" : "https://www.ibm.com/support/pages/node/7284580"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-384" ],
    "severity" : "CRITICAL",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-08-28T22:16:46Z"
  }
}