# CVE-1999-0241: X Window System guessable magic cookies remote command execution

Source: https://junglewise.ai/threats/cve-1999-0241-x-window-system-guessable-magic-cookies-remote-command-execution  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 1995-11-01. Updated: 2026-05-10  
License: CC BY 4.0 with a link back

CVE-1999-0241 · Severity: critical · CVSS 10 · Published 1995-11-01

A vulnerability in the X Window System, a graphical interface used on Unix and Linux systems, allows remote attackers to gain unauthorized access to a user's session. By guessing the security tokens (magic cookies) used to authenticate connections, an attacker can remotely execute commands on the victim's machine. This could lead to a complete system takeover, theft of sensitive data, or the installation of malicious software.

Technologies: [Sgi Irix](https://junglewise.ai/threats/technologies/irix), [Sunos](https://junglewise.ai/threats/technologies/sunos). Vendors: [Sgi](https://junglewise.ai/threats/vendors/sgi), [Sun](https://junglewise.ai/threats/vendors/sun), [X.Org Foundation](https://junglewise.ai/threats/vendors/x-org-foundation).

## Quick answers

**Is CVE-1999-0241 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-1999-0241 being exploited in the wild.

**How severe is CVE-1999-0241?** Critical severity, with a CVSS score of 10, published 1 November 1995.

**Which products and versions are affected?** X.Org X Window System (X11); Sun Microsystems Solaris 2.6; Sun Microsystems SunOS.

**Is there a fix for CVE-1999-0241?** 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-1999-0241 attacked?** It is attacked over the network, in an operating system.

**Am I affected by CVE-1999-0241?** Check whether you run Sgi Irix, Sunos, X.Org Foundation X Window System or one of the others listed. 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

The X Window System (X11) uses a cookie-based authentication mechanism (MIT-MAGIC-COOKIE-1) to control access to the X server. This vulnerability arises because the 'magic cookies' generated are sufficiently predictable or have low entropy, making them susceptible to brute-force or guessing attacks. A remote attacker who successfully guesses a valid cookie can connect to the X server and interact with the session. This allows for various attacks, including capturing keystrokes, viewing the screen, or injecting commands into terminal emulators like xterm to achieve remote code execution. This issue is historically significant in early Unix environments and SunOS/Solaris configurations.

## Affected products

- X.Org X Window System (X11)
- Sun Microsystems Solaris 2.6
- Sun Microsystems SunOS

## Timeline

- 1995-11-01: disclosed: Initial publication date in NVD

## References

- [https://exchange.xforce.ibmcloud.com/vulnerabilities/CVE-1999-0241](https://exchange.xforce.ibmcloud.com/vulnerabilities/CVE-1999-0241)

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