CVE-2026-91018

Received Received - Intake

Double Free Vulnerability in lwIP TCP/IP Stack

Publication date: 2026-09-22

Last updated on: 2026-09-22

Assigner: ICS-CERT

Description

lwIP (Lightweight IP) has a double free vulnerability, which could crash the system, cause a DoS, memory corruption, or allow code execution on the victim system.

CVSS Scores

EPSS Scores

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Meta Information

Published

2026-09-22

Last Modified

2026-09-22

Generated

2026-09-23

AI Q&A

2026-09-23

EPSS Evaluated

N/A

NVD

CVE-2026-91018

Affected Vendors & Products

Vendor	Product	Version / Range
lwip	lwip	*

Helpful Resources

Exploitability

CWE

KEV

CWE ID	Description
CWE-415	The product calls free() twice on the same memory address.

Attack-Flow Graph

Executive Summary

lwIP (Lightweight IP) has a double free vulnerability. This means the software incorrectly frees the same memory block twice, which can lead to system crashes, denial of service, memory corruption, or potential code execution by attackers.

Detection Guidance

Detection of this lwIP double free vulnerability may require network traffic analysis or system monitoring. Check for unusual crashes, memory corruption, or DoS events in lwIP-based systems. Monitor for abnormal network behavior or crashes in embedded devices using lwIP.

Impact Analysis

This vulnerability could allow attackers to crash your system, disrupt services through denial of service, corrupt memory leading to instability, or execute malicious code on your device if exploited.

Compliance Impact

This vulnerability could lead to unauthorized access, data breaches, or system crashes, which may violate GDPR's integrity and confidentiality requirements or HIPAA's security rules for protected health information.

Mitigation Strategies

Immediately update lwIP to the latest patched version. If an update is unavailable, disable affected network services using lwIP or restrict network access to vulnerable systems. Monitor vendor advisories for patches or workarounds.

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