Detections
Analytics

Curl 7.14.1 < 8.20.0 Proxy Credential Disclosure

high Nessus Plugin ID 311419

Synopsis

The remote host has a program that is affected by a proxy credential disclosure vulnerability

Description

The version of curl installed on the remote host is 7.14.1 prior to 8.20.0. It is, therefore, affected by a proxy credential disclosure vulnerability:

 - curl might erroneously pass on credentials for a first proxy to a second proxy. This flaw occurs when different proxies are configured for different URL schemes, the first proxy requires authentication, the second proxy does not need credentials, and a redirect occurs from one URL scheme to another. The credentials are transmitted in base64-encoded form to the unintended proxy. (CVE-2026-6253)

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-2026-6253.html

Plugin Details

Severity: High

ID: 311419

File Name: curl_CVE-2026-6253.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

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

CVSS Score Source: CVE-2026-6253

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:curl

Required KB Items: installed_sw/Curl

Patch Publication Date: 4/29/2026

Vulnerability Publication Date: 4/29/2026

Reference Information

CVE: CVE-2026-6253

IAVA: 2026-A-0397