CVE-2022-44313 is a medium-severity vulnerability identified in PicoC version 3.2.2, an embeddable C interpreter often used in embedded systems and applications requiring lightweight scripting capabilities. The vulnerability is a heap-based buffer overflow occurring in the ExpressionCoerceUnsignedInteger function within expression.c, specifically when invoked via ExpressionParseFunctionCall. This function is responsible for coercing expressions to unsigned integers during parsing. A heap buffer overflow here means that the function writes more data to a heap-allocated buffer than it can hold, potentially corrupting adjacent memory. This can lead to application crashes or undefined behavior, including denial of service (DoS). According to the CVSS v3.1 vector (AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H), the vulnerability requires local access (AV:L), low attack complexity (AC:L), no privileges (PR:N), but does require user interaction (UI:R). The impact is limited to availability (A:H), with no confidentiality or integrity impact. No known exploits are currently reported in the wild, and no vendor or product information beyond PicoC 3.2.2 is specified. The lack of patch links suggests that a fix may not yet be publicly available or widely distributed. The vulnerability is classified under CWE-787 (Out-of-bounds Write).

For European organizations, the primary impact of this vulnerability is the potential for denial of service in systems embedding PicoC 3.2.2. Since PicoC is typically used in embedded or specialized environments, organizations relying on devices or applications that incorporate this interpreter could experience service interruptions or crashes if an attacker can trigger the vulnerable function. The requirement for local access and user interaction limits remote exploitation, reducing the risk of widespread attacks. However, in environments where users have local access to affected systems—such as industrial control systems, research labs, or development environments—this vulnerability could be leveraged to disrupt operations. The absence of confidentiality and integrity impacts means data theft or manipulation is unlikely directly from this flaw. Nevertheless, availability disruptions in critical infrastructure or industrial settings could have cascading effects. European organizations with embedded device deployments or custom applications using PicoC should assess their exposure. Given the medium severity and limited exploitation scope, the threat is moderate but should not be ignored, especially in sectors with critical uptime requirements.

1. Inventory and Identification: Conduct a thorough inventory of embedded systems, applications, and devices within the organization to identify any that use PicoC version 3.2.2. 2. Restrict Local Access: Since exploitation requires local access and user interaction, enforce strict access controls on devices running PicoC, limiting user permissions and physical access. 3. User Training: Educate users with local access about the risks of interacting with untrusted inputs or scripts that could trigger the vulnerable function. 4. Input Validation and Hardening: Where possible, implement additional input validation or sandboxing around scripting interfaces that utilize PicoC to prevent malformed expressions from reaching the vulnerable code path. 5. Monitor for Crashes: Deploy monitoring to detect abnormal application crashes or behavior indicative of heap corruption, enabling rapid incident response. 6. Patch Management: Stay alert for official patches or updates from PicoC maintainers or third parties and apply them promptly once available. 7. Alternative Solutions: For critical systems, consider replacing PicoC with more actively maintained or secure scripting engines if feasible. 8. Limit User Interaction: Minimize scenarios where untrusted users can interact with the vulnerable function, such as disabling scripting features where not essential.