CVE-2026-86121: Software Security Vulnerability Vulnerability

CRITICAL
Advisory Identifier: GHSA-pccw-h89v-h9cj
Share
CVSS 9.8
CWE-306
Published
Advisory Summary

CVE-2026-86121 is a CRITICAL (CVSS 9.8) security vulnerability vulnerability (CWE-306: Missing Authentication for Critical Function) affecting Software libraries in the Maven ecosystem. The weakness occurs when the product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.. Remediation is available in the latest vendor maintenance releases.

CVE-2026-86121 at a Glance

CVE Identifier CVE-2026-86121
GHSA Identifier GHSA-pccw-h89v-h9cj
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-306: Missing Authentication for Critical Function
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

Security Impact

CVSS: 9.8

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

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

How to Fix CVE-2026-86121

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-2026-86121, 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-306: Missing Authentication for Critical Function, where the product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources. 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

Cua computer-server versions before 0.3.42 skip authentication when the CONTAINER_NAME environment variable is unset and bind to all interfaces by default, allowing unauthenticated attackers to execute arbitrary commands. Attackers can reach TCP port 8000 to run shell commands via the run_command endpoint, read and write arbitrary files through file operation endpoints, and access interactive PTY shells without authentication.

References

NVD — CVE-2026-86121 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-86121
Software Source Repository REPOSITORY
https://github.com/trycua/cua/issues/1892
Security Fix Commit FIX COMMIT
https://github.com/trycua/cua/commit/59cf25c0ec54
Software Source Repository REPOSITORY
https://github.com/trycua/cua
Software Source Repository REPOSITORY
https://github.com/trycua/cua/blob/10a2e71792db/libs/python/computer-server/computer_server/cli.py
Software Source Repository REPOSITORY
https://github.com/trycua/cua/blob/10a2e71792db/libs/python/computer-server/computer_server/main.py
www.vulncheck.com/advisories/cua-comp... WEB
https://www.vulncheck.com/advisories/cua-computer-server-before-0.3.42-unauthenticated-rce-via-desktop-control

Frequently Asked Questions

What is CVE-2026-86121?
CVE-2026-86121 is a security vulnerability in Software classified as a security vulnerability vulnerability under CWE-306: Missing Authentication for Critical Function.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-86121?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What is the CVSS score of CVE-2026-86121?
CVE-2026-86121 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2026-86121?
CVE-2026-86121 is classified under CWE-306: Missing Authentication for Critical Function (The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.).
How can I check Maven dependencies for CVE-2026-86121?
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-pccw-h89v-h9cj",
  "modified" : "2026-09-05T12:31:26Z",
  "published" : "2026-09-05T12:31:26Z",
  "aliases" : [ "CVE-2026-86121" ],
  "details" : "Cua computer-server versions before 0.3.42 skip authentication when the CONTAINER_NAME environment variable is unset and bind to all interfaces by default, allowing unauthenticated attackers to execute arbitrary commands. Attackers can reach TCP port 8000 to run shell commands via the run_command endpoint, read and write arbitrary files through file operation endpoints, and access interactive PTY shells without authentication.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  }, {
    "type" : "CVSS_V4",
    "score" : "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X"
  } ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-86121"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/trycua/cua/issues/1892"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/trycua/cua/commit/59cf25c0ec54"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/trycua/cua"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/trycua/cua/blob/10a2e71792db/libs/python/computer-server/computer_server/cli.py"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/trycua/cua/blob/10a2e71792db/libs/python/computer-server/computer_server/main.py"
  }, {
    "type" : "WEB",
    "url" : "https://www.vulncheck.com/advisories/cua-computer-server-before-0.3.42-unauthenticated-rce-via-desktop-control"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-306" ],
    "severity" : "CRITICAL",
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-05T10:16:43Z"
  }
}