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High DLA-4373-1 2 CVEs

libwebsockets - security update

Published Nov 17, 2025 · Updated Nov 17, 2025

Fixed packages 1

ReleasePackageFixed in
Debian · 11 libwebsockets 4.0.20-2+deb11u1

Vulnerabilities 2

  • High 7.5

    Stack-based Buffer Overflow in libwebsockets DNS response parsing

    Stack-based Buffer Overflow in lws_adns_parse_label in warmcat libwebsockets allows, when the LWS_WITH_SYS_ASYNC_DNS flag is enabled during compilation, to overflow the label_stack, when the attacker is able to sniff a DNS request in order to craft a response…

  • Medium 6.3

    Use After Free in libwebsockets WebSocket server

    Use After Free in WebSocket server implementation in lws_handshake_server in warmcat libwebsockets may allow an attacker, in specific configurations where the user provides a callback function that handles LWS_CALLBACK_HTTP_CONFIRM_UPGRADE, to achieve denial …