---
id: "CVE-2026-87423"
kind: "vulnerability"
aliases: ["CVE-2026-87423"]
title: "Oracle Solaris 11.4: X Window System flaw lets local users alter data"
severity: "medium"
cvss: 4.5
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "on-prem", "oracle", "solaris", "x-window-system"]
not_affected_if: ["no-untrusted-local-users", "no-x-window-system"]
published_at: "2026-10-20T22:20:20+00:00"
first_seen_at: "2026-10-23T21:57:26+00:00"
updated_at: "2026-10-25T04:35:37+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-87423", "first_seen_at": "2026-10-23T21:57:26+00:00"}]
---

# Oracle Solaris 11.4: X Window System flaw lets local users alter data

A flaw in the X Window System component of Oracle Solaris 11.4 lets a low-privileged local user read, change or partly disrupt data the system can access. Exploitation is hard and requires the attacker to already have a logon on the machine.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Run `pkg info entire` on the Solaris host to confirm the installed release is 11.4
- Check whether the X Window System packages are installed with `pkg list | grep -i xorg`

## Fix

- Apply the latest Oracle Solaris 11.4 Support Repository update (version unknown from the sources)
- Check the Oracle Critical Patch Update advisory for the patch that addresses this CVE

## Timeline

- 2026-10-23T21:57:26+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-87423

## From the sources

Vulnerability in the Oracle Solaris product of Oracle Systems (component: X Window System).   The supported version that is affected is 11.4. Difficult to exploit vulnerability allows low privileged attacker with logon to the infrastructure where Oracle Solaris executes to compromise Oracle Solaris.  Successful attacks of this vulnerability can result in  unauthorized update, insert or delete access to some of Oracle Solaris accessible data as well as  unauthorized read access to a subset of Oracle Solaris accessible data and unauthorized ability to cause a partial denial of service (partial DOS) of Oracle Solaris. CVSS 3.1 Base Score 4.5 (Confidentiality, Integrity and Availability impacts).  CVSS Vector: (CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L).

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_