CVE-2021-41556

sqclass.cpp in Squirrel through 2.2.5 and 3.x through 3.1 allows an out-of-bounds read (in the core interpreter) that can lead to Code Execution. If a victim executes an attacker-controlled squirrel script, it is possible for the attacker to break out of the squirrel script sandbox even if all dangerous functionality such as File System functions has been disabled. An attacker might abuse this bug to target (for example) Cloud services that allow customization via SquirrelScripts, or distribute malware through video games that embed a Squirrel Engine.

• CWE-125
• CWE-125

• http://www.squirrel-lang.org/#downloadThird Party Advisory
• https://blog.sonarsource.com/squirrel-vm-sandbox-escape/Exploit, Third Party Advisory
• https://github.com/albertodemichelis/squirrel/commit/23a0620658714b996d20da3d4dd1a0dcf9b0bd98Patch, Third Party Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BV7SJJ44AGAX4ILIVPREIXPJ2GOG3FKV/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M3FQILX7UUEERSDPMZP3MKGTMY2E7ESU/
• http://www.squirrel-lang.org/#downloadThird Party Advisory
• https://blog.sonarsource.com/squirrel-vm-sandbox-escape/Exploit, Third Party Advisory
• https://github.com/albertodemichelis/squirrel/commit/23a0620658714b996d20da3d4dd1a0dcf9b0bd98Patch, Third Party Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BV7SJJ44AGAX4ILIVPREIXPJ2GOG3FKV/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/M3FQILX7UUEERSDPMZP3MKGTMY2E7ESU/
• https://www.sonarsource.com/blog/squirrel-vm-sandbox-escape/

Published

Jul 28, 2022

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
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