CVE-2022-44320 is a medium-severity vulnerability identified in PicoC version 3.2.2, an embedded C interpreter often used in lightweight scripting environments within embedded systems or constrained devices. The vulnerability is a heap-based buffer overflow occurring in the ExpressionCoerceFP function located in expression.c. This function is invoked during the parsing of function calls via ExpressionParseFunctionCall. Specifically, the overflow arises when floating-point coercion operations are performed on expressions, leading to memory corruption on the heap. The vulnerability is classified under CWE-787 (Out-of-bounds Write), indicating that the software writes data past the boundary of allocated heap memory. Exploitation requires local access (Attack Vector: Local) and no privileges (PR:N), but user interaction is necessary (UI:R), such as triggering the vulnerable function through crafted input or scripts. The impact is limited to availability (A:H), meaning successful exploitation can cause crashes or denial of service, but does not affect confidentiality or integrity. The CVSS 3.1 base score is 5.5, reflecting a medium severity level. No known public exploits or patches have been reported as of the publication date (November 8, 2022). Given the nature of PicoC as an embedded interpreter, the vulnerability could be triggered in environments where PicoC is embedded and exposed to user-supplied scripts or inputs that invoke floating-point coercion during expression parsing. The heap overflow could lead to application crashes or instability, potentially disrupting device functionality or service availability. However, exploitation complexity is moderate due to the need for local access and user interaction, limiting remote exploitation scenarios. No vendor or product information is specified, indicating this vulnerability is tied to the open-source PicoC interpreter itself rather than a specific commercial product. This requires organizations using PicoC embedded in their products or systems to assess exposure and apply mitigations accordingly.

For European organizations, the primary impact of CVE-2022-44320 lies in potential denial of service conditions on embedded devices or systems utilizing PicoC 3.2.2. This could affect industrial control systems, IoT devices, or specialized equipment that rely on embedded scripting for automation or configuration. Disruptions could lead to operational downtime, impacting manufacturing, utilities, or critical infrastructure sectors. Since the vulnerability does not compromise confidentiality or integrity, data breaches or unauthorized modifications are unlikely. However, availability impacts could degrade service reliability or cause safety concerns in critical environments. The requirement for local access and user interaction limits the risk of widespread remote exploitation, but insider threats or compromised local users could trigger the vulnerability. European organizations deploying embedded systems with PicoC should be aware of this risk, especially in sectors with high reliance on embedded scripting such as manufacturing, automotive, or telecommunications. The lack of known exploits reduces immediate risk, but the presence of a heap overflow vulnerability necessitates proactive risk management to prevent potential denial of service or system instability.

Conduct an inventory of embedded systems and products using PicoC version 3.2.2 or earlier to identify affected devices. Where possible, upgrade to a newer version of PicoC that addresses this vulnerability or apply vendor-provided patches once available. If no patch is available, implement input validation and sanitization on any user-supplied scripts or data that invoke expression parsing to prevent triggering the vulnerable code path. Restrict local access to devices running PicoC to trusted users only, employing strong access control and monitoring to detect unauthorized or suspicious activity. Implement application-level sandboxing or process isolation to contain potential crashes and prevent cascading failures in embedded environments. Monitor device logs and behavior for signs of crashes or instability that may indicate exploitation attempts. Engage with device or system vendors to confirm the presence of this vulnerability and request security updates or mitigations. Develop incident response procedures specific to embedded device failures to minimize operational impact in case of exploitation.