Detections
Analytics
Curl 8.21.0 < 8.23.0 Multiple Connection Reuse Vulnerabilities
critical Nessus Plugin ID 371159
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Synopsis
The remote host has a program that is affected by multiple connection reuse vulnerabilities.Description
The version of curl installed on the remote host is 8.21.0 prior to 8.23.0. It is, therefore, affected by multiple connection reuse vulnerabilities:- libcurl's connection cache match function never considers the automatic client certificate option, so a cached, already authenticated Schannel connection can be handed to a transfer that got redirected to a different origin, even though the code explicitly switched off the auto client cert option for that transfer to prevent exactly this. (CVE-2026-86415)
- When using ambient user credentials, an HTTP request directed to one origin may be dispatched over a connection previously authenticated via Negotiate for a different origin, leaving the request's intended credentials unused. (CVE-2026-87861)
Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.
Solution
Upgrade Curl to version 8.23.0 or later.See Also
Plugin Details
Severity: Critical
ID: 371159
File Name: curl_8_21_0.nasl
Version: 1.1
Type: Local
Agent: windows, macosx, unix
Family: Misc.
Published: 10/23/2026
Updated: 10/23/2026
Configuration: Enable thorough checks (optional)
Supported Sensors: Nessus Agent, Continuous Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus
Risk Information
CVSS Score Rationale: Score from an analysis done by tenable
VPR
Risk Factor: High
Score: 7.7
Percentile: 98.9
CVSS v3
Risk Factor: Critical
Base Score: 9.1
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N
Vulnerability Information
CPE: cpe:/a:haxx:curl
Required KB Items: installed_sw/Curl
Patch Publication Date: 10/14/2026
Vulnerability Publication Date: 10/14/2026
Reference Information
CVE: CVE-2026-86415, CVE-2026-87861
IAVA: 2026-A-1143