Detections
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libcurl 8.17.0 < 8.21.0 Native CA Trust Persist

critical Nessus Plugin ID 322999

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Synopsis

The remote host has a program that is affected by an improper certificate validation vulnerability.

Description

The version of libcurl installed on the remote host is 8.17.0 prior to 8.21.0. It is, therefore, affected by an improper certificate validation vulnerability:

 - An easy handle that first uses default native CA trust can continue trusting the native platform store after the application switches that same handle to custom CA material for a later transfer.
 (CVE-2026-11564)

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-2026-11564.html

Plugin Details

Severity: Critical

ID: 322999

File Name: libcurl_CVE-2026-11564.nasl

Version: 1.3

Type: Local

Agent: windows, macosx, unix

Family: Misc.

Published: 6/26/2026

Updated: 7/8/2026

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: Medium

Score: 4.3

Percentile: 53.66

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5

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

CVSS Score Source: CVE-2026-11564

CVSS v3

Risk Factor: Critical

Base Score: 9.1

Temporal Score: 8.2

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

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

Vulnerability Information

CPE: cpe:/a:haxx:libcurl

Required KB Items: installed_sw/libcurl

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 6/24/2026

Vulnerability Publication Date: 6/24/2026

Reference Information

CVE: CVE-2026-11564

IAVA: 2026-A-0627