---
id: "CVE-2026-91209"
kind: "vulnerability"
aliases: ["CVE-2026-91209"]
title: "Oracle Solaris X Window System flaw lets local users alter data"
severity: "medium"
cvss: 4.2
epss: null
exploited: false
status: "open"
category: "infrastructure"
products: []
ecosystems: []
tags: ["infrastructure", "on-prem", "oracle-solaris", "solaris", "x-window-system"]
not_affected_if: ["headless-server", "no-x-window-system"]
published_at: "2026-10-20T22:20:21+00:00"
first_seen_at: "2026-10-23T21:57:26+00:00"
updated_at: "2026-10-25T04:41:32+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-91209", "first_seen_at": "2026-10-23T21:57:26+00:00"}]
---

# Oracle Solaris 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 with logon access affect data the system can reach. The attacker can read, change or delete some data and partly disrupt service, but only when another person takes part in the attack.

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

## How to check

- Run `pkgparam` or `pkg info entire` on the Solaris host to confirm the installed release is `11.4`
- unknown

## Fix

- Apply the Oracle Critical Patch Update for Solaris 11.4 that covers this CVE (patch ID unknown from the sources)
- unknown

## Timeline

- 2026-10-23T21:57:26+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-91209

## 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 require human interaction from a person other than the attacker. 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 4.2 (Confidentiality, Integrity and Availability impacts).  CVSS Vector: (CVSS:3.1/AV:L/AC:H/PR:L/UI:R/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_