Cyber Resilience

CVE-2026-9541

Memory Safety in Squirrel-Lang Squirrel ≤ 3.2

Public PoCMemory Safety
Published
26 May 2026
Modified
23 July 2026
Patch / advisory
CVSS Score v4 1.9
Click a component to see what it means
Raw vectorCVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0017 7th percentile
Risk Priority 15 floored blend · peak EPSS

Summary

CVE-2026-9541 is a low-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Squirrel-Lang Squirrel. Its CVSS base score is 1.9 (Low).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-16 (Memory Protection) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

A security flaw has been discovered in Squirrel up to 3.2. Impacted is the function ReadObject of the file squirrel/sqobject.cpp of the component Cnut File Handler. Performing a manipulation results in heap-based buffer overflow. The attack is only possible with…

more

local access. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
Why these techniques?

Local heap buffer overflow in file handler enables local privilege escalation via crafted input.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1068 Exploitation for Privilege Escalation Privilege Escalationconfidence: HIGH
Heap buffer overflow in a local file handler can be directly leveraged for local privilege escalation.
T1204.002 Malicious File Executionconfidence: MEDIUM
Successful exploitation requires a user to open or process a malicious Cnut file, constituting user execution of a malicious file.
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-2661Same product: Squirrel-Lang Squirrel
CVE-2026-2659Same product: Squirrel-Lang Squirrel
CVE-2024-45421Shared CWE-119, CWE-122
CVE-2025-6816Shared CWE-119, CWE-122
CVE-2026-3994Shared CWE-119, CWE-122
CVE-2026-15506Shared CWE-119, CWE-122
CVE-2026-8087Shared CWE-119, CWE-122
CVE-2026-13574Shared CWE-119, CWE-122
CVE-2026-8261Shared CWE-119, CWE-122
CVE-2026-3407Shared CWE-119, CWE-122

Affected Assets

squirrel-lang
squirrel
≤ 3.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-10 Information Input Validation
  • SI-16 Memory Protection
  • AC-6 Least Privilege
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V17.3.2
  • V1.4.1

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly enforces validation of untrusted Cnut file contents before ReadObject processes them, blocking the malformed input that triggers the heap buffer overflow.

prevent

Applies memory protections (e.g., bounds checking, ASLR/DEP) that prevent successful exploitation of the heap-based overflow in sqobject.cpp.

prevent

Restricts privileges of processes that invoke the Cnut File Handler, limiting the impact of any local buffer-overflow exploit.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 full match
prevents

Secure-development practices directly require bounds checking and safe memory handling that prevent heap overflows.

ID.RA-01 partial match
prevents

Vulnerability scanning and code analysis directly surface buffer-boundary flaws.

ID.RA-08 partial match
prevents

Receiving and triaging vulnerability disclosures commonly includes buffer-related reports.

PR.AT-02 partial match
prevents

Developer training on secure coding reduces introduction of memory-buffer errors.

PR.PS-02 partial match
prevents

Patching replaces vulnerable code containing buffer-boundary defects.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

detects

Security testing in development catches out-of-bounds accesses before release, covering most instances of the weakness.

prevents

Secure development lifecycle mandates memory-safety practices that directly prevent buffer-boundary violations.

prevents

Application security requirements can specify memory-safety rules, but do not prescribe implementation details.

prevents

Secure architecture and engineering principles include memory-safe design patterns that mitigate buffer overflows.

prevents

Secure coding standards explicitly forbid unsafe buffer operations, directly eliminating CWE-119.

none

Change management ensures controlled deployment of fixes for discovered heap-overflow vulnerabilities.

References