CVE-2026-2661
Published: 18 February 2026
Summary
CVE-2026-2661 is a medium-severity Improper Restriction of Operations within the Bounds of a Memory Buffer (CWE-119) vulnerability in Squirrel-Lang Squirrel. Its CVSS base score is 4.8 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked at the 1.4th 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 are NIST 800-53 SI-16 (Memory Protection) and CM-7 (Least Functionality).
Deeper analysis
CVE-2026-2661 is a heap-based buffer overflow vulnerability in the Squirrel scripting language library, specifically affecting the SQObjectPtr::operator function in squirrel/sqobject.h. It impacts Squirrel versions up to and including 3.2 and is associated with CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) and CWE-122 (Heap-based Buffer Overflow).
The vulnerability requires local access (AV:L) with low attack complexity (AC:L) and low privileges (PR:L), needing no user interaction (UI:N) and resulting in no scope change (S:U). An attacker can achieve a denial-of-service condition impacting availability (A:L), with no effects on confidentiality or integrity, as reflected in its CVSS v3.1 base score of 3.3.
Advisories indicate the Squirrel project was informed early via GitHub issue #310 (https://github.com/albertodemichelis/squirrel/issues/310) but has not responded or released patches. A proof-of-concept exploit reproduction is publicly available (https://github.com/oneafter/0122/blob/main/i310/repro), and VulDB details the issue (https://vuldb.com/?ctiid.346459, https://vuldb.com/?id.346459, https://vuldb.com/?submit.753165). No specific mitigations are provided beyond avoiding affected versions.
The exploit has been released publicly and may be used for attacks, published on 2026-02-18.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-7641
Vulnerability details
A security flaw has been discovered in Squirrel up to 3.2. This affects the function SQObjectPtr::operator in the library squirrel/sqobject.h. The manipulation results in heap-based buffer overflow. The attack needs to be approached locally. The exploit has been released to…
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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
Why these techniques?
Heap buffer overflow in Squirrel library enables local exploitation to crash the host application, directly mapping to application/system exploitation for endpoint DoS (no RCE or escalation per CVSS).
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly enforces memory protections (e.g., ASLR, guard pages, safe allocators) that block exploitation of the heap-based buffer overflow in SQObjectPtr::operator.
Requires bounds checking and sanitization on inputs passed to Squirrel library functions, mitigating the root cause of the CWE-122 overflow before it occurs.
Restricts installation and execution of the vulnerable Squirrel <=3.2 component to only those systems where it is explicitly required, reducing the local attack surface.