CVE-2026-1998 is a memory corruption vulnerability identified in the micropython interpreter, affecting all versions up to and including 1.27.0. The vulnerability resides in the mp_import_all function located in the py/runtime.c source file. This function is responsible for handling the import of all symbols from a module during Python script execution. Improper handling or manipulation of this function can lead to memory corruption, which may cause the interpreter to crash or behave unpredictably. The attack vector is local, requiring an attacker to have local access and at least limited privileges on the system running micropython. No user interaction or network access is needed, but the attacker must be able to execute code locally. The vulnerability does not directly lead to privilege escalation or remote code execution but can be leveraged as part of a larger attack chain. The patch identified by commit 570744d06c5ba9dba59b4c3f432ca4f0abd396b6 addresses this issue by correcting the memory handling in the affected function. Although no active exploits have been reported in the wild, a proof-of-concept exploit has been published, increasing the risk of exploitation. Micropython is widely used in embedded systems, IoT devices, and educational environments, making this vulnerability relevant to those sectors. The CVSS 4.0 vector indicates low attack complexity and local attack vector with no privileges required beyond local access, no user interaction, and limited impact on confidentiality, integrity, and availability.

For European organizations, the impact of CVE-2026-1998 depends largely on the extent of micropython deployment in embedded and IoT devices within their infrastructure. Industrial automation, smart building controls, and educational technology platforms using micropython could experience service disruptions or device malfunctions if exploited. Memory corruption can lead to denial of service conditions or unpredictable device behavior, potentially affecting operational continuity and safety-critical systems. While the vulnerability does not directly enable remote exploitation or privilege escalation, it could be used by an insider or attacker with local access to destabilize devices or as a stepping stone in a multi-stage attack. Given the growing adoption of micropython in European manufacturing and smart city projects, the vulnerability poses a moderate risk to operational technology environments. The lack of known exploits in the wild reduces immediate threat levels but does not eliminate the risk, especially in sensitive or high-value environments.

European organizations should prioritize patching micropython installations to versions beyond 1.27.0 where the vulnerability is fixed. Since the attack requires local access, organizations should enforce strict access controls on devices running micropython, limiting user privileges and physical access. Network segmentation should be employed to isolate embedded devices and IoT endpoints running micropython from critical infrastructure and administrative networks. Implement monitoring for unusual local activity or crashes related to micropython processes to detect potential exploitation attempts. For development and deployment, adopt secure coding and testing practices to identify memory handling issues early. Additionally, consider using hardware security features such as secure boot and trusted execution environments to reduce the risk of local exploitation. Regularly review and update device firmware and software to incorporate security patches promptly. Finally, educate staff on the risks of local exploitation and the importance of maintaining device security hygiene.