CVE-2026-2661 identifies a heap-based buffer overflow vulnerability in the Squirrel scripting language, specifically affecting versions 3.0 through 3.2. The vulnerability is located in the SQObjectPtr::operator function within the squirrel/sqobject.h source file. This function improperly handles memory operations, allowing an attacker with local access and low privileges to manipulate heap memory beyond its allocated bounds. Such heap overflows can corrupt adjacent memory, potentially leading to application crashes, data corruption, or arbitrary code execution if exploited effectively. The attack vector requires local access, meaning the attacker must have some form of access to the host system, but no elevated privileges or user interaction are necessary. The vulnerability was responsibly disclosed early to the Squirrel project, but no patch or official response has been issued as of the publication date. A public exploit has been released, increasing the risk of exploitation by attackers with local access. The CVSS 4.8 score reflects the medium severity, with low attack complexity but limited to local attack vector and requiring privileges. Squirrel is often embedded in applications and games for scripting purposes, so the impact depends on how and where Squirrel is deployed. The lack of a patch means organizations must rely on containment and mitigation until an official fix is available.

For European organizations, the impact of this vulnerability depends largely on the extent to which Squirrel is embedded in their software products or development environments. Organizations using Squirrel in embedded systems, IoT devices, or custom applications may face risks of local attackers exploiting this flaw to execute arbitrary code or cause denial of service. This could lead to system instability, data corruption, or unauthorized control over affected applications. Given the local attack requirement, the threat is more significant in environments where multiple users have local access or where attackers can gain initial footholds via other means. Critical infrastructure or industrial control systems using Squirrel-based components could be at risk of disruption. The public availability of an exploit increases the urgency for mitigation. However, the medium severity and local access requirement limit the scope compared to remote vulnerabilities. Still, organizations should assess their exposure, especially in sectors with high security requirements such as finance, manufacturing, and telecommunications.

Since no official patch is currently available, European organizations should implement specific mitigations to reduce risk. First, restrict local access to systems running Squirrel to trusted users only, employing strict access controls and monitoring. Use application whitelisting and endpoint detection to identify suspicious activity related to Squirrel processes. Employ sandboxing or containerization to isolate applications using Squirrel, limiting the impact of potential exploitation. Review and update internal policies to minimize the number of users with local access privileges. Conduct code audits and testing on applications embedding Squirrel to identify if and how the vulnerable function is used, and consider disabling or replacing Squirrel where feasible. Monitor security advisories for updates or patches from the Squirrel project and plan for rapid deployment once available. Additionally, implement robust logging and anomaly detection to detect exploitation attempts early. For critical systems, consider network segmentation to limit lateral movement from compromised hosts.