Detections
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libcurl 7.12.0 < 8.20.0 Cross-Proxy Digest Auth State Leak

critical Nessus Plugin ID 311422

Synopsis

The remote host has a program that is affected by a cross-proxy digest auth state leak vulnerability.

Description

The version of libcurl installed on the remote host is 7.12.0 prior to 8.20.0. It is, therefore, affected by a cross-proxy digest auth state leak vulnerability:

 - libcurl improperly handles Digest authentication headers when reusing handles across different HTTP proxies. When a client switches from one proxy to another using the same connection handle, the library incorrectly forwards the Proxy-Authorization header intended for the first proxy to the second one. An evil proxyB could use this incoming request header field to impersonate the client in communicating with proxyA, as the header contains the authenticated state. (CVE-2026-7168)

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 8.20.0 or later

See Also

https://curl.se/docs/CVE-2026-7168.html

Plugin Details

Severity: Critical

ID: 311422

File Name: libcurl_CVE-2026-7168.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: 6.4

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

CVSS Score Source: CVE-2026-7168

CVSS v3

Risk Factor: Critical

Base Score: 9.8

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

Vulnerability Information

CPE: cpe:/a:haxx:libcurl

Required KB Items: installed_sw/libcurl

Patch Publication Date: 4/29/2026

Vulnerability Publication Date: 4/29/2026

Reference Information

CVE: CVE-2026-7168

IAVA: 2026-A-0397