sqclass.cpp in Squirrel through 2.2.5 and 3.x through 3.1 allows an out-of-bounds read…
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA.
Summary
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.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- Poc
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 3
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:squirrel-lang:squirrel:*:*:*:*:*:*:*:* | up to 2.2.5; 3.0 – 3.1 | Vulnerable | Squirrel-lang |
| cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* | 35 | Vulnerable | Fedoraproject |
| cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:* | 36 | Vulnerable | Fedoraproject |
- cpe:2.3:a:squirrel-lang:squirrel:*:*:*:*:*:*:*:* Versions up to 2.2.5; 3.0 – 3.1 Vulnerable ·Squirrel-lang
- cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* Versions 35 Vulnerable ·Fedoraproject
- cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:* Versions 36 Vulnerable ·Fedoraproject
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2021-41556
- 2026-10-03 Alias added: GHSA-cm28-mc8h-9h49
References
Sources
- CVE-2021-41556 · CVE Program
- CVE-2021-41556 · NVD
- FIRST EPSS
- GHSA-cm28-mc8h-9h49 · GitHub Advisory Database · CC BY 4.0
- CVE-2021-41556 · Red Hat security data · CC BY 4.0
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