CVE catalog

CVE-2021-41556

DEBIAN-CVE-2021-41556

Severity: Critical · CVSS 10CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
Published: Jan 1, 2021, 12:00:00 AM UTC
Updated: Sep 1, 2026, 8:04:33 PM UTC
Source: [NVD] · [CVE record]
EPSS: 2.84% · Oct 25, 2026

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.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	squirrel3	13	`3.1-8.2`	vulnerable
Debian	squirrel3	13	`3.1-8.2+deb13u1`	fixed
Debian	squirrel3	14	`3.1-8.2`	vulnerable
Debian	squirrel3	14	`3.1-8.3`	vulnerable
Debian	squirrel3	14	`3.1-8.4`	vulnerable
Debian	squirrel3	14	`3.1-8.5`	fixed
Suse	squirrel	package hub 15 sp4	`3.0.7-bp154.3.3.1`	fixed
Opensuse	squirrel	leap 15.4	`3.0.7-bp154.3.3.1`	fixed
Opensuse	squirrel	tumbleweed	`3.2-1.1`	fixed

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	squirrel3	deb	13	`3.1-8.2+deb13u1`	Not reported	DEBIAN-CVE-2021-41556	Not reported
Debian	squirrel3	deb	14	`3.1-8.5`	Not reported	DEBIAN-CVE-2021-41556	Not reported
Suse	squirrel	rpm	package hub 15 sp4	`3.0.7-bp154.3.3.1`	Not reported	OPENSUSE-SU-2023:0080-1	Not reported
Opensuse	squirrel	rpm	leap 15.4	`3.0.7-bp154.3.3.1`	Not reported	OPENSUSE-SU-2023:0080-1	Not reported
Opensuse	squirrel	rpm	tumbleweed	`3.2-1.1`	Not reported	OPENSUSE-SU-2024:12611-1	Not reported

OpenFactory catalog packages

[openSUSE Tumbleweed]

[libsquirrel1001]Unknown
Source package: [squirrel]
Details (1)
- 3.2-4.5 · x86_64 · tumbleweed
  Unknown · Fixed: 3.2-1.1
  Version impact unknown
  pypi · squirrel · opensuse · tumbleweed
[squirrel-devel]Unknown
Source package: [squirrel]
Details (1)
- 3.2-4.5 · x86_64 · tumbleweed
  Unknown · Fixed: 3.2-1.1
  Version impact unknown
  pypi · squirrel · opensuse · tumbleweed
[squirrel-doc]Unknown
Source package: [squirrel]
Details (1)
- 3.2-4.5 · noarch · tumbleweed
  Unknown · Fixed: 3.2-1.1
  Version impact unknown
  pypi · squirrel · opensuse · tumbleweed
[squirrel-examples]Unknown
Source package: [squirrel]
Details (1)
- 3.2-4.5 · noarch · tumbleweed
  Unknown · Fixed: 3.2-1.1
  Version impact unknown
  pypi · squirrel · opensuse · tumbleweed
[squirrel]Fixed
Source package: [squirrel]
Details (1)
- 3.2-4.5 · x86_64 · tumbleweed
  Fixed · Fixed: 3.2-1.1
  pypi · squirrel · opensuse · tumbleweed

[Debian 13 (Trixie)]

[libsquirrel3-0]Fixed
Source package: [squirrel3]
Details (2)
- 3.1-8.2+deb13u1 · amd64 · trixie
  Fixed · Fixed: 3.1-8.2+deb13u1
  pypi · squirrel3 · debian · 13
- 3.1-8.2+deb13u1 · arm64 · trixie
  Fixed · Fixed: 3.1-8.2+deb13u1
  pypi · squirrel3 · debian · 13
[libsquirrel-dev]Fixed
Source package: [squirrel3]
Details (2)
- 3.1-8.2+deb13u1 · amd64 · trixie
  Fixed · Fixed: 3.1-8.2+deb13u1
  pypi · squirrel3 · debian · 13
- 3.1-8.2+deb13u1 · arm64 · trixie
  Fixed · Fixed: 3.1-8.2+deb13u1
  pypi · squirrel3 · debian · 13
[squirrel3]Fixed
Details (2)
- 3.1-8.2+deb13u1 · amd64 · trixie
  Fixed · Fixed: 3.1-8.2+deb13u1
  pypi · squirrel3 · debian · 13
- 3.1-8.2+deb13u1 · arm64 · trixie
  Fixed · Fixed: 3.1-8.2+deb13u1
  pypi · squirrel3 · debian · 13

Observed: Oct 23, 2026, 6:02:51 PM UTC

References

[FIRST EPSS] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]