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  • lwIP (Lightweight IP)

    From Cisa Advisories@2:263/1 to All on Tue Sep 22 17:03:06 2026
    lwIP (Lightweight IP)

    View CSAF
    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 Free

    Metrics




    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




    Legal Notice and Terms of Use

    https://www.cisa.gov/news-events/ics-advisories/icsa-26-265-02

    2026-09-22 12:00 UTC

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    * Origin: LISTS. from TCOB1 READ ONLY (2:263/1)