CVE-2026-2659 identifies a vulnerability in the Squirrel scripting language, versions 3.0 to 3.2, located in the SQFuncState::PopTarget function within the source file sqfuncstate.cpp. The issue stems from improper validation or manipulation of the _target_stack argument, which can lead to an out-of-bounds read condition. This type of vulnerability allows an attacker to read memory beyond the intended buffer boundaries, potentially exposing sensitive information or causing application instability. The attack vector is local, requiring the attacker to have low-level privileges on the host system, and no user interaction is necessary to trigger the vulnerability. The vulnerability was responsibly disclosed early to the project maintainers, but as of the publication date, no official patch or fix has been released. The CVSS 4.0 vector indicates low attack complexity, no user interaction, and limited privileges required, resulting in a medium severity rating with a base score of 4.8. No known exploits are currently observed in the wild, but the public disclosure increases the risk of exploitation attempts. The vulnerability affects all three listed versions of Squirrel, which is often embedded in applications and games for scripting purposes.

The primary impact of CVE-2026-2659 is the potential for information disclosure through out-of-bounds memory reads. While it does not directly enable code execution or privilege escalation, attackers with local access could leverage this vulnerability to glean sensitive data from memory, which might include cryptographic keys, credentials, or other confidential information depending on the context in which Squirrel is used. This could lead to further attacks or compromise of the host system. The vulnerability could also cause application crashes or instability, affecting availability. Organizations embedding Squirrel in their products or using it internally may face risks of data leakage and reduced system reliability. Since exploitation requires local access and low privileges, remote attackers are unlikely to exploit this directly, but insider threats or compromised local accounts could pose a risk. The lack of an official patch increases the window of exposure.

Given the absence of an official patch, organizations should implement several practical mitigations: 1) Restrict local access to systems running vulnerable versions of Squirrel by enforcing strict access controls and monitoring for unauthorized local logins. 2) Employ application sandboxing or containerization to limit the impact of any out-of-bounds reads within isolated environments. 3) Conduct thorough code audits and consider applying manual code fixes or patches if feasible, focusing on validating _target_stack arguments to prevent out-of-bounds conditions. 4) Monitor system and application logs for unusual behavior or crashes related to Squirrel processes. 5) If possible, upgrade to a newer, unaffected version of Squirrel once available or consider alternative scripting engines with active maintenance. 6) Educate developers and system administrators about the vulnerability and the importance of minimizing local privilege exposure. 7) Implement memory protection mechanisms such as Address Space Layout Randomization (ASLR) and Data Execution Prevention (DEP) to reduce exploitation success.