Summary
Successful exploitation of this vulnerability could result in a system crash, a DoS, or memory corruption, which could lead to code execution on the victim system.The following versions of lwIP (Lightweight IP) are affected:
- API >=2.0.1|<=2.2.1 (CVE-2026-91018)
CVSS
Vendor
Equipment
Vulnerabilities
v3 8.8
lwIP
lwIP (Lightweight IP)
Double Free
Background
- Critical Infrastructure Sectors: Chemical, Communications, Critical Manufacturing, Energy, Financial Services, Healthcare and Public Health, Transportation Systems, Water and Wastewater Systems
- Countries/Areas Deployed: Worldwide
- Company Headquarters Location: Sweden
Vulnerabilities
Expand All +
CVE-2026-91018
The affected product has a double free vulnerability, which could crash the system, cause a DoS, memory corruption, or allow code execution on the victim system.
View CVE Details
Affected Products
lwIP (Lightweight IP)
Vendor:lwIP
Product Version:lwIP API: >=2.0.1|<=2.2.1
Product Status:known_affected
Remediations
MitigationUsers of lwIP are encouraged to update their version of lwIP using the repository found at https://cgit.git.savannah.gnu.org/cgit/lwip.git. The commit identifier that contains the fix is f873b6295933e4149a2132adf3e9a2d2a676a5ec.
Relevant CWE: CWE-415 Double FreeMetrics
CVSS Version
Base Score
Base Severity
Vector String
3.1
8.8
HIGH
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
4.0
8.7
HIGH
CVSS:4.0/AV:A/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
Acknowledgments
- Eric Evenchick of Tetrel Security reported this vulnerability to CISA.
Legal Notice and Terms of Use
This product is provided subject to this Notification (https://www.cisa.gov/notification) and this Privacy & Use policy (https://www.cisa.gov/privacy-policy).
Recommended Practices
CISA recommends users take defensive measures to minimize the risk of exploitation of this vulnerability.
- Minimize network exposure for all control system devices and/or systems, ensuring they are not accessible from the internet.
- Locate control system networks and remote devices behind firewalls and isolating them from business networks.
- When remote access is required, use more secure methods, such as Virtual Private Networks (VPNs), recognizing VPNs may have vulnerabilities and should be updated to the most current version available. Also recognize VPN is only as secure as the connected devices.
CISA reminds organizations to perform proper impact analysis and risk assessment prior to deploying defensive measures.
CISA also provides a section for control systems security recommended practices on the ICS webpage on cisa.gov/ics. Several CISA products detailing cyber defense best practices are available for reading and download, including Improving Industrial Control Systems Cybersecurity with Defense-in-Depth Strategies.
CISA encourages organizations to implement recommended cybersecurity strategies for proactive defense of ICS assets.
Additional mitigation guidance and recommended practices are publicly available on the ICS webpage at cisa.gov/ics in the technical information paper, ICS-TIP-12-146-01B--Targeted Cyber Intrusion Detection and Mitigation Strategies.
Organizations observing suspected malicious activity should follow established internal procedures and report findings to CISA for tracking and correlation against other incidents.
CISA also recommends users take the following measures to protect themselves from social engineering attacks:
- Do not click web links or open attachments in unsolicited email messages.
- Refer to Recognizing and Avoiding Email Scams for more information on avoiding email scams.
- Refer to Avoiding Social Engineering and Phishing Attacks for more information on social engineering attacks.
No known public exploitation specifically targeting this vulnerability has been reported to CISA at this time. This vulnerability is not exploitable remotely.
Revision History
- Initial Release Date: 2026-09-22
Date
Revision
Summary
2026-09-22
1
Initial Publication