# CVE-2026-87423: Oracle Solaris privilege escalation in X Window System

Source: https://junglewise.ai/threats/cve-2026-87423-vulnerability-in-the-oracle-solaris-product-of-oracle-systems  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-10-20. Updated: 2026-10-20  
License: CC BY 4.0 with a link back

CVE-2026-87423 · Severity: medium · CVSS 4.5 · Published 2026-10-20

Oracle Solaris is the Unix operating system used in enterprise data centers to run critical applications and services. A local vulnerability in the X Window System (the graphical display system) allows an attacker with low-level system access to read sensitive data, modify system information, and disrupt service availability. An attacker would need legitimate login access to the system to exploit this weakness.

Technologies: [Oracle Solaris](https://junglewise.ai/threats/technologies/solaris). Vendors: [Oracle](https://junglewise.ai/threats/vendors/oracle).

## Quick answers

**Is CVE-2026-87423 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-87423 being exploited in the wild.

**How severe is CVE-2026-87423?** Medium severity, with a CVSS score of 4.5, published 20 October 2026.

**Which products and versions are affected?** Oracle Solaris 11.4.

**Is there a fix for CVE-2026-87423?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2026-87423 attacked?** It is attacked with local access, in an operating system.

**Am I affected by CVE-2026-87423?** Check whether you run Oracle Solaris at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A local privilege escalation vulnerability exists in the X Window System component of Oracle Solaris 11.4, requiring low privilege and local logon access with difficult exploitation. Successful exploitation grants unauthorized read access to system data, ability to modify accessible data, and capability to cause partial denial of service. The vulnerability is exploitable only by authenticated local users and does not appear to have a public exploit in the wild.

## Affected products

- Oracle Solaris 11.4

## Timeline

- 2026-10-20: disclosed

## References

- [https://www.oracle.com/security-alerts/cpuoct2026.html](https://www.oracle.com/security-alerts/cpuoct2026.html)

## Related threats

- [Oracle Solaris privilege escalation in utility component](https://junglewise.ai/threats/cve-2026-91537-vulnerability-in-the-oracle-solaris-product-of-oracle-systems)
- [Oracle Solaris privilege escalation in Utility component](https://junglewise.ai/threats/cve-2026-91348-vulnerability-in-the-oracle-solaris-product-of-oracle-systems)
- [Oracle Solaris privilege escalation in Utility component](https://junglewise.ai/threats/cve-2026-91336-vulnerability-in-the-oracle-solaris-product-of-oracle-systems)
- [Oracle Solaris denial of service in Libraries component](https://junglewise.ai/threats/cve-2026-91324-vulnerability-in-the-oracle-solaris-product-of-oracle-systems)
- [Oracle Solaris Services denial of service and information disclosure](https://junglewise.ai/threats/cve-2026-91256-vulnerability-in-the-oracle-solaris-product-of-oracle-systems)