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    CVE-2026-6985

    A weakness has been identified in Cesanta Mongoose up to 7.20. This vulnerability affects the function handle_opt of the file /src/net_builtin.c of the component TCP Option Handler. This manipulation of the argument optlen causes infinite loop. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 7.21 is able to resolve this issue. Upgrading the affected component is advised. VulDB has contacted the vendor early and they confirmed quickly, that this issue got fixed already.

    Published:Apr 25, 2026
    Last Modified:Apr 27, 2026
    EPS:Apr 25, 2026
    EPSS Score:0.00042
    CVSS Score:5.3

    Affected Products

    Vendor
    Cesanta
    Product
    Mongoose

    Exploits

    https://github.com/dwBruijn/CVEs/blob/main/Mongoose/TCP_opt_dos.md

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    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High