Linux Distros Unpatched Vulnerability : CVE-2026-19931

critical Nessus Plugin ID 342437

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Synopsis

The Linux/Unix host has one or more packages installed with a vulnerability that the vendor indicates will not be patched.

Description

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

- A flaw in libcurl makes it wrongly reuse an HTTP connection setup for a given hostname using Negotiate authentication, when the initial request is done using empty credentials. This can make user B's request get sent over user A's previously authenticated connection. (CVE-2026-19931)

Note that Nessus relies on the presence of the package as reported by the vendor.

Solution

There is no known solution at this time.

Plugin Details

Severity: Critical

ID: 342437

File Name: unpatched_CVE_2026_19931.nasl

Version: 1.10

Type: Local

Agent: unix

Family: Misc.

Published: 9/2/2026

Updated: 9/23/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Tenable Cloud Security, Tenable Self-Hosted Container Security, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 4.9

Percentile: 58.22

CVSS v2

Risk Factor: Medium

Base Score: 4

Temporal Score: 3.6

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

CVSS Score Source: CVE-2026-19931

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 9.3

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

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

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:20.04:-:lts, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:canonical:ubuntu_linux:26.04:-:lts, cpe:/o:debian:debian_linux:12.0, cpe:/o:debian:debian_linux:13.0, cpe:/o:redhat:enterprise_linux:10, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:canonical:ubuntu_linux:curl, p-cpe:/a:debian:debian_linux:curl, p-cpe:/a:redhat:enterprise_linux:curl-minimal, p-cpe:/a:redhat:enterprise_linux:curl, p-cpe:/a:redhat:enterprise_linux:igvm, p-cpe:/a:redhat:enterprise_linux:libcurl-devel, p-cpe:/a:redhat:enterprise_linux:libcurl-minimal, p-cpe:/a:redhat:enterprise_linux:libcurl, p-cpe:/a:redhat:enterprise_linux:snphost

Required KB Items: Host/local_checks_enabled, Host/cpu, global_settings/vendor_unpatched, Host/OS/identifier

Exploit Available: true

Exploit Ease: Exploits are available

Reference Information

CVE: CVE-2026-19931

Detections

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