Detections
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libcurl 8.16.0 < 8.21.0 WebSocket Auto-PONG Memory Exhaustion (CVE-2026-11586)

high Nessus Plugin ID 326239

Synopsis

The remote host has a library that is affected by a denial of service vulnerability.

Description

The version of libcurl installed on the remote host is 8.16.0 prior to 8.21.0. It is, therefore, affected by a denial of service vulnerability:

 - By default, curl automatically responds to WebSocket PING frames. Because curl lacks an upper bound on memory allocation for unacknowledged frames, a malicious server can exhaust all available memory by flooding curl with rapid, sequential PING messages. (CVE-2026-11586)

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

Solution

Upgrade libcurl to version 8.21.0 or later.

See Also

https://curl.se/docs/CVE-2026-11586.html

Plugin Details

Severity: High

ID: 326239

File Name: libcurl_CVE-2026-11586.nasl

Version: 1.1

Type: Local

Agent: windows, macosx, unix

Family: Misc.

Published: 7/10/2026

Updated: 7/10/2026

Configuration: Enable thorough checks (optional)

Supported Sensors: Continuous Assessment, Nessus Agent, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.75

CVSS v2

Risk Factor: High

Base Score: 7.8

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

CVSS Score Source: CVE-2026-11586

CVSS v3

Risk Factor: High

Base Score: 7.5

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

Vulnerability Information

CPE: cpe:/a:haxx:libcurl

Required KB Items: installed_sw/libcurl

Patch Publication Date: 6/24/2026

Vulnerability Publication Date: 6/24/2026

Reference Information

CVE: CVE-2026-11586

IAVA: 2026-A-0627