{"id":"CVE-2026-13217","title":"NULL-pointer dereference in Zephyr OCPP CALLRESULT parsing via unchecked strtok_r/atoi","summary":"The OCPP 1.6 client in subsys/net/lib/ocpp/ocpp.c reconstructs a session handle and PDU id from the uid field of a CALLRESULT message. In ocpp_process_server_msg() the code calls atoi(strtok_r(uid, \"-\", &tmp)) without checking the strtok…","severity":"medium","cvss":5.9,"cvssVector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H","cvssSource":"cna","cwe":["CWE-476"],"vendor":"zephyrproject","product":"zephyr","affected":["zephyr >= 4.3.0 < 4.3.2","zephyr >= 4.4.0 < 4.4.2"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-08-25T19:40:23.470690Z"},"published":"2026-08-25","updated":"2026-11-04","sourceUpdated":"2026-11-04T04:59:46.392Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2026-13217","references":[{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/4d8a9eb1448061ccee557ef20a2a58aec91d9cad","label":"Fix commit 4d8a9eb14480"},{"url":"https://github.com/zephyrproject-rtos/zephyr/commit/eba36f8ed63a055ed862ab2b4bb801b6dce07bb7","label":"Fix commit eba36f8ed63a"},{"url":"https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-w234-pcxp-4q8r","label":"GHSA-w234-pcxp-4q8r"}],"tags":["cve.org"],"epss":0.00667,"epssPercentile":0.5205,"ingestedAt":"2026-11-05T20:33:06.707Z","slug":"CVE-2026-13217","body":"## Overview\n\nThe OCPP 1.6 client in subsys/net/lib/ocpp/ocpp.c reconstructs a session handle and PDU id from the uid field of a CALLRESULT message. In ocpp_process_server_msg() the code calls atoi(strtok_r(uid, \"-\", &tmp)) without checking the strtok_r return value. When the server-supplied uid is empty or contains no - delimiter, strtok_r() returns NULL and atoi(NULL) dereferences a NULL pointer, which is undefined behaviour.\n\nThe uid originates from network data: parse_rpc_msg() in subsys/net/lib/ocpp/ocpp_j.c JSON-parses a frame received from the OCPP central system over TCP/WebSocket and copies the server-controlled string into the local buffer. A malicious or compromised central system, or a man-in-the-middle on a non-TLS ws:// connection, can return a malformed uid to reach the defect. No authentication beyond the existing server connection (or MITM position) is required, and the reconstructed pointer is membership-validated by ocpp_session_is_valid(), so the impact is limited to the NULL dereference rather than arbitrary pointer use.\n\nOn Zephyr targets that trap access to address 0 (MMU/MPU platforms or CONFIG_NULL_POINTER_EXCEPTION_DETECTION), the dereference faults inside the OCPP reader thread and invokes the fatal handler, producing a remote denial of service of the charge point; on bare targets where address 0 is readable the call returns 0 and is benign, so the impact is availability-only and platform-conditional.\n\nThe applied fix guards only the first atoi(); the second strtok_r(NULL, \"-\", &tmp) followed by pdu = atoi(buf) in the same function remains unguarded and the identical NULL dereference is still reachable from the same network input when the uid has a first token but no second --delimited token. A complete fix should validate the second token as well.\n\n## Affected\n\n- `zephyr >= 4.3.0 < 4.3.2`\n- `zephyr >= 4.4.0 < 4.4.2`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":33,"depthScoreParts":{"impact":32.5,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}