CVE-2023-26819 is a vulnerability identified in the cJSON library version 1.7.15, a widely used lightweight JSON parser written in C. The issue stems from an expected behavior violation classified under CWE-440, where the library improperly handles crafted JSON input containing extremely large numeric values within arrays. For example, a JSON document like {"a": true, "b": [ null, 9999999999999999999999999999999999999999999999912345678901234567]} can trigger this vulnerability. The excessive numeric value causes the parser to consume excessive resources, potentially leading to a denial of service (DoS) condition by exhausting memory or CPU cycles during parsing. The CVSS v3.1 score is 2.9 (low severity), reflecting that exploitation requires local access (AV:L), high attack complexity (AC:H), no privileges (PR:N), and no user interaction (UI:N). The vulnerability impacts availability only, with no confidentiality or integrity compromise. No known exploits have been reported in the wild, and no official patches have been released as of the publication date. This vulnerability is particularly relevant for applications or embedded systems that use cJSON 1.7.15 to parse untrusted or external JSON data, as crafted input could disrupt service availability. The lack of a patch necessitates temporary mitigations such as input validation and limiting resource consumption during JSON parsing.

For European organizations, the primary impact of CVE-2023-26819 is the potential for denial of service in systems relying on cJSON 1.7.15 for JSON parsing. This could affect embedded devices, IoT systems, or software components that process external JSON data without sufficient input validation. Disruptions could lead to service outages, impacting operational continuity, especially in critical infrastructure sectors such as manufacturing, automotive, telecommunications, and healthcare. Since the vulnerability requires local access and has high attack complexity, remote exploitation is unlikely, reducing the risk of widespread attacks. However, insider threats or compromised internal systems could leverage this vulnerability to degrade service availability. The absence of confidentiality or integrity impact limits the risk to data breaches or manipulation. European organizations with supply chains or products incorporating cJSON should assess their exposure and implement mitigations to prevent service interruptions.

1. Implement strict input validation to reject JSON documents containing excessively large numeric values or unusually large arrays before parsing with cJSON. 2. Enforce resource limits on memory and CPU usage during JSON parsing to prevent exhaustion from malicious inputs. 3. Where possible, sandbox or isolate components using cJSON to contain potential denial of service effects. 4. Monitor application logs and system performance for signs of abnormal resource consumption related to JSON parsing. 5. Engage with cJSON maintainers or vendors for updates and apply patches promptly once available. 6. Consider upgrading to a later, patched version of cJSON or alternative JSON parsers with better input handling if feasible. 7. For embedded systems, review firmware update mechanisms to enable timely deployment of fixes. 8. Educate developers and system integrators about safe JSON handling practices and this specific vulnerability.