Debian dla-4373 : libwebsockets-dev - security update

high Nessus Plugin ID 275575

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Synopsis

The remote Debian host is missing one or more security-related updates.

Description

The remote Debian 11 host has packages installed that are affected by multiple vulnerabilities as referenced in the dla-4373 advisory.

- ----------------------------------------------------------------------- Debian LTS Advisory DLA-4373-1 [email protected] https://www.debian.org/lts/security/ Utkarsh Gupta November 17, 2025 https://wiki.debian.org/LTS
- -----------------------------------------------------------------------

Package : libwebsockets Version : 4.0.20-2+deb11u1 CVE ID : CVE-2025-11677 CVE-2025-11678 Debian Bug : 1118746 1118747

Libwebsockets (LWS) is a flexible, lightweight pure C library for implementing modern network protocols easily with a tiny footprint, using a nonblocking event loop.

CVE-2025-11677

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 of service.

CVE-2025-11678

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 with a matching ID containing a label longer than the maximum.

For Debian 11 bullseye, these problems have been fixed in version 4.0.20-2+deb11u1.

We recommend that you upgrade your libwebsockets packages.

For the detailed security status of libwebsockets please refer to its security tracker page at:
https://security-tracker.debian.org/tracker/libwebsockets

Further information about Debian LTS security advisories, how to apply these updates to your system and frequently asked questions can be found at: https://wiki.debian.org/LTS

Tenable has extracted the preceding description block directly from the Debian security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Upgrade the libwebsockets-dev packages.

Plugin Details

Severity: High

ID: 275575

File Name: debian_DLA-4373.nasl

Version: 1.1

Type: local

Agent: unix

Family: Debian Local Security Checks

Published: 11/17/2025

Updated: 11/17/2025

Supported Sensors: Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 5.9

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

CVSS Score Source: CVE-2025-11677

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

CVSS v4

Risk Factor: High

Base Score: 7.5

Threat Score: 4.8

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS Score Source: CVE-2025-11678

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, p-cpe:/a:debian:debian_linux:libwebsockets-dev, p-cpe:/a:debian:debian_linux:libwebsockets-test-server, p-cpe:/a:debian:debian_linux:libwebsockets-test-server-common, p-cpe:/a:debian:debian_linux:libwebsockets16

Required KB Items: Host/local_checks_enabled, Host/Debian/release, Host/Debian/dpkg-l

Exploit Ease: No known exploits are available

Patch Publication Date: 11/17/2025

Vulnerability Publication Date: 10/20/2025

Reference Information

CVE: CVE-2025-11677, CVE-2025-11678

Detections

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