Detections
Analytics

Curl 7.10.6 < 8.20.0 Wrong Reuse of HTTP Negotiate Connection

high Nessus Plugin ID 311425

Synopsis

The remote host has a program that is affected by an authentication bypass vulnerability

Description

The version of curl installed on the remote host is 7.10.6 prior to 8.20.0. It is, therefore, affected by an authentication bypass vulnerability:

 - libcurl might in some circumstances reuse the wrong connection when asked to do an authenticated HTTP(S) request after a Negotiate-authenticated one, when both use the same host. When an application first authenticates to a server using Negotiate with one set of credentials and then makes a subsequent request with different credentials, libcurl may inappropriately reuse the earlier connection, resulting in the new request being sent over a connection still authenticated for the original user.
 (CVE-2026-5545)

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

Solution

Upgrade Curl to version 8.20.0 or later

See Also

https://curl.se/docs/CVE-2026-5545.html

Plugin Details

Severity: High

ID: 311425

File Name: curl_CVE-2026-5545.nasl

Version: 1.1

Type: Local

Agent: windows, macosx, unix

Family: Misc.

Published: 5/1/2026

Updated: 5/1/2026

Configuration: Enable thorough checks (optional)

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: Medium

Base Score: 5.5

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

CVSS Score Source: CVE-2026-5545

CVSS v3

Risk Factor: High

Base Score: 8.8

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

Vulnerability Information

CPE: cpe:/a:haxx:curl

Required KB Items: installed_sw/Curl

Patch Publication Date: 4/29/2026

Vulnerability Publication Date: 4/29/2026

Reference Information

CVE: CVE-2026-5545

IAVA: 2026-A-0397