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OpenAdvisories
Critical · 10.0 CVE-2021-41556 EUVD-2021-28574GHSA-cm28-mc8h-9h49

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 Exec…

Published Jul 28, 2022 · Updated May 29, 2026 · Assigned by mitre

Description

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.

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 13 squirrel3 3.1-8.2+deb13u1 —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 squirrel3 No fix yet —
Ubuntu 26.04 LTS squirrel3 No fix yet —
Ubuntu 25.10 squirrel3 No fix yet —
Ubuntu 22.04 LTS squirrel3 No fix yet —
Ubuntu 20.04 LTS squirrel3 No fix yet —
Show 1 more (older releases, extended support, other products)
ReleasePackageFixed inAdvisory
Ubuntu 18.04 LTS squirrel3 No fix yet —
ReleasePackageFixed inAdvisory
SUSE Package Hub 15 SP4 squirrel 3.0.7-bp154.3.3.1 openSUSE-SU-2023:0080-1
ReleasePackageFixed inAdvisory
openSUSE Tumbleweed squirrel 3.2-1.1 openSUSE-SU-2024:12611-1
openSUSE Leap 15.4 squirrel 3.0.7-bp154.3.3.1 openSUSE-SU-2023:0080-1

Advisories 2

References