A security vulnerability was discovered in Ubuntu versions 20.04, 18.04, and 16.04 that affects Dungeon Crawl Stone Soup. The game could be made to execute arbitrary code by opening a specially crafted file due to incorrect handling of Lua bytecode. David Mendenhall discovered the issue, which could potentially allow an attacker to run malicious software. To fix the problem, users can update their system to the latest package versions using a standard system update.

[USN-7969-1] Dungeon Crawl Stone Stoup vulnerability

[USN-7969-1] Dungeon Crawl Stone Stoup vulnerability

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Ubuntu Security Notice USN-7969-1
January 19, 2026

crawl vulnerability
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A security issue affects these releases of Ubuntu and its derivatives:

- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS

Summary:

Dungeon Crawl Stone Soup could be made to execute arbitrary code if it
opened a specially crafted file.

Software Description:
- crawl: a text-based roguelike game

Details:

David Mendenhall discovered that Dungeon Crawl Stone Soup was incorrectly
handling Lua bytecode embedded in an uploaded .crawlrc file. An attacker
could possibly use this issue to execute arbitrary code.

Update instructions:

The problem can be corrected by updating your system to the following
package versions:

Ubuntu 20.04 LTS
crawl 2:0.24.0-1ubuntu0.1~esm1
Available with Ubuntu Pro
crawl-common 2:0.24.0-1ubuntu0.1~esm1
Available with Ubuntu Pro
crawl-tiles 2:0.24.0-1ubuntu0.1~esm1
Available with Ubuntu Pro
crawl-tiles-data 2:0.24.0-1ubuntu0.1~esm1
Available with Ubuntu Pro

Ubuntu 18.04 LTS
crawl 2:0.21.1-1ubuntu0.1~esm1
Available with Ubuntu Pro
crawl-common 2:0.21.1-1ubuntu0.1~esm1
Available with Ubuntu Pro
crawl-tiles 2:0.21.1-1ubuntu0.1~esm1
Available with Ubuntu Pro
crawl-tiles-data 2:0.21.1-1ubuntu0.1~esm1
Available with Ubuntu Pro

Ubuntu 16.04 LTS
crawl 2:0.17.1-1ubuntu0.1~esm1
Available with Ubuntu Pro
crawl-common 2:0.17.1-1ubuntu0.1~esm1
Available with Ubuntu Pro
crawl-tiles 2:0.17.1-1ubuntu0.1~esm1
Available with Ubuntu Pro
crawl-tiles-data 2:0.17.1-1ubuntu0.1~esm1
Available with Ubuntu Pro

In general, a standard system update will make all the necessary changes.

References:
https://ubuntu.com/security/notices/USN-7969-1
CVE-2020-11722