Detections
Analytics

libcurl 8.18.0 < 8.21.0 Persistent Referer Header Information Disclosure

high Nessus Plugin ID 323000

Synopsis

The remote host has a program that is affected by an information disclosure vulnerability.

Description

The version of libcurl installed on the remote host is 8.18.0 prior to 8.21.0. It is, therefore, affected by an information disclosure vulnerability:

 - A vulnerability in libcurl caused the HTTP Referer header to persist even when explicitly cleared, potentially leaking sensitive information to unintended servers. (CVE-2026-9546)

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-2026-9546.html

Plugin Details

Severity: High

ID: 323000

File Name: libcurl_CVE-2026-9546.nasl

Version: 1.1

Type: Local

Agent: windows, macosx, unix

Family: Misc.

Published: 6/26/2026

Updated: 6/26/2026

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: 5.0

CVSS v2

Risk Factor: Medium

Base Score: 5

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

CVSS Score Source: CVE-2026-9546

CVSS v3

Risk Factor: High

Base Score: 7.5

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

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-2026-9546

IAVA: 2026-A-0627