CVE-2026-1998 in micropython
Summary
by MITRE • 02/06/2026
A flaw has been found in micropython up to 1.27.0. This vulnerability affects the function mp_import_all of the file py/runtime.c. This manipulation causes memory corruption. The attack needs to be launched locally. The exploit has been published and may be used. Patch name: 570744d06c5ba9dba59b4c3f432ca4f0abd396b6. It is suggested to install a patch to address this issue.
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Analysis
by VulDB Data Team • 02/18/2026
The vulnerability identified as CVE-2026-1998 represents a critical memory corruption flaw within the MicroPython runtime environment affecting versions up to 1.27.0. This issue specifically targets the mp_import_all function located in the py/runtime.c file, which serves as a fundamental component for module importing operations within the MicroPython interpreter. The flaw manifests when the runtime processes certain import operations, creating conditions that lead to unpredictable memory behavior and potential system instability. The vulnerability's local attack requirement means that exploitation necessitates access to the target system, typically through legitimate user credentials or physical access, though the availability of published exploits increases the threat surface significantly. This type of vulnerability falls under CWE-121, which describes heap-based buffer overflow conditions, and can potentially enable attackers to execute arbitrary code or cause denial of service through memory corruption. The patch referenced as 570744d06c5ba9dba59b4c3f432ca4f0abd396b6 specifically addresses the memory management issue in the import handling mechanism, providing a fix that prevents the corruption of memory structures during module import operations.
The operational impact of this vulnerability extends beyond simple system instability, as it can enable attackers with local access to potentially escalate privileges or manipulate the execution flow of MicroPython applications. Given that MicroPython is commonly deployed in embedded systems, IoT devices, and microcontroller environments where security may be limited, this vulnerability presents a significant risk to device integrity and data confidentiality. The memory corruption could lead to unpredictable behavior in applications that rely on MicroPython for scripting and automation, potentially allowing attackers to inject malicious code or cause system crashes that could disrupt critical operations. From an attacker's perspective, this vulnerability aligns with ATT&CK technique T1059.007 for script-based execution and T1068 for local privilege escalation, making it particularly dangerous in environments where MicroPython is used for system automation or control functions. The fact that exploits are publicly available means that this vulnerability can be weaponized by threat actors without requiring advanced technical skills, increasing the likelihood of successful attacks against unpatched systems.
Mitigation strategies for CVE-2026-1998 should prioritize immediate patch application to all affected MicroPython installations, particularly those deployed in production environments or critical infrastructure. System administrators should conduct comprehensive inventory assessments to identify all systems running vulnerable MicroPython versions and prioritize patch deployment according to risk assessment criteria. Additional protective measures include implementing strict access controls to prevent unauthorized local execution, monitoring system logs for unusual import operations or memory-related errors, and considering network segmentation to limit the potential impact of successful local exploitation. Organizations should also review their MicroPython usage patterns and implement runtime monitoring to detect anomalous behavior that might indicate exploitation attempts. The vulnerability demonstrates the importance of maintaining up-to-date firmware and software in embedded environments, where traditional security controls may be insufficient. Security teams should also consider implementing automated patch management systems to ensure timely remediation of similar vulnerabilities across their MicroPython-based deployments. Regular security assessments of embedded systems and IoT devices that utilize MicroPython should include checks for vulnerable versions to prevent exploitation through supply chain or operational security gaps.