Detections
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Curl 7.40.0 < 8.20.0 Wrong SMB Connection Reuse

high Nessus Plugin ID 311423

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Synopsis

The remote host has a program that is affected by a wrong SMB connection reuse vulnerability

Description

The version of curl installed on the remote host is 7.40.0 prior to 8.20.0. It is, therefore, affected by a wrong SMB connection reuse vulnerability:

 - libcurl might in some circumstances reuse the wrong connection for SMB(S) transfers. The code erroneously did not consider the share name as a property to match for connection reuse, so subsequent SMB transfers could incorrectly reuse connections intended for different shares on the same server.
 This could result in downloading incorrect files or uploading files to unintended locations.
 (CVE-2026-5773)

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-2026-5773.html

Plugin Details

Severity: High

ID: 311423

File Name: curl_CVE-2026-5773.nasl

Version: 1.3

Type: Local

Agent: windows, macosx, unix

Family: Misc.

Published: 5/1/2026

Updated: 5/14/2026

Configuration: Enable thorough checks (optional)

Supported Sensors: Nessus Agent, Continuous Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.1

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

CVSS Score Source: CVE-2026-5773

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.7

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

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

Vulnerability Information

CPE: cpe:/a:haxx:curl

Required KB Items: installed_sw/Curl

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 4/29/2026

Vulnerability Publication Date: 4/29/2026

Reference Information

CVE: CVE-2026-5773

IAVA: 2026-A-0397