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Linux Distros Unpatched Vulnerability : CVE-2026-86818

medium Nessus Plugin ID 345871

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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.

 - fast-uri is a dependency-free RFC 3986 URI parser for Node.js, used by Fastify and ajv, that added a mailto scheme parser in version 4.1.3. In versions 4.1.3 and 4.1.4, the mailto parser compares each query field name to the reserved names to, subject, and body while the name is still percent-encoded, and decodes it only when storing it as a generic header, so a percent-encoded spelling of a reserved field name is not recognized as that field at parse time but is re-emitted as the literal field name when the parsed URI is serialized. An application that validates, logs, or displays the recipient list from the first parse and then serializes the URI and sends it can silently gain an attacker-chosen recipient, and the subject and body fields can be smuggled across the same roundtrip. The issue is fixed in fast-uri 4.1.5, and users should upgrade to 4.1.5 or later. As a workaround, do not act on a mailto URI that fast- uri has re-serialized without first decoding and re-validating its recipient, subject, and body fields.
 (CVE-2026-86818)

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

Solution

There is no known solution at this time.

See Also

https://access.redhat.com/security/cve/cve-2026-86818

Plugin Details

Severity: Medium

ID: 345871

File Name: unpatched_CVE_2026_86818.nasl

Version: 1.2

Type: Local

Agent: unix

Family: Misc.

Published: 9/15/2026

Updated: 9/16/2026

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: Low

Score: 2.1

Percentile: 8.02

CVSS v2

Risk Factor: Medium

Base Score: 4

Temporal Score: 3.4

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

CVSS Score Source: CVE-2026-86818

CVSS v3

Risk Factor: Medium

Base Score: 4.8

Temporal Score: 4.4

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

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

Vulnerability Information

CPE: cpe:/o:centos:centos:8, cpe:/o:redhat:enterprise_linux:10, cpe:/o:redhat:enterprise_linux:8, cpe:/o:redhat:enterprise_linux:9, p-cpe:/a:centos:centos:aspnetcore-runtime-8.0, p-cpe:/a:centos:centos:aspnetcore-runtime-dbg-8.0, p-cpe:/a:centos:centos:aspnetcore-targeting-pack-8.0, p-cpe:/a:centos:centos:cockpit-image-builder, p-cpe:/a:centos:centos:dotnet-apphost-pack-8.0, p-cpe:/a:centos:centos:dotnet-host, p-cpe:/a:centos:centos:dotnet-hostfxr-8.0, p-cpe:/a:centos:centos:dotnet-runtime-8.0, p-cpe:/a:centos:centos:dotnet-runtime-dbg-8.0, p-cpe:/a:centos:centos:dotnet-sdk-8.0-source-built-artifacts, p-cpe:/a:centos:centos:dotnet-sdk-8.0, p-cpe:/a:centos:centos:dotnet-sdk-dbg-8.0, p-cpe:/a:centos:centos:dotnet-targeting-pack-8.0, p-cpe:/a:centos:centos:dotnet-templates-8.0, p-cpe:/a:centos:centos:dotnet8.0, p-cpe:/a:centos:centos:dotnet, p-cpe:/a:centos:centos:grafana-pcp, p-cpe:/a:centos:centos:grafana-selinux, p-cpe:/a:centos:centos:grafana, p-cpe:/a:centos:centos:linux-sgx, p-cpe:/a:centos:centos:netstandard-targeting-pack-2.1, p-cpe:/a:centos:centos:sgx-common, p-cpe:/a:centos:centos:sgx-libs, p-cpe:/a:centos:centos:sgx-mpa, p-cpe:/a:centos:centos:sgx-pccs-admin, p-cpe:/a:centos:centos:sgx-pccs, p-cpe:/a:centos:centos:sgx-pckid-tool, p-cpe:/a:centos:centos:tdx-qgs, p-cpe:/a:redhat:enterprise_linux:aspnetcore-runtime-8.0, p-cpe:/a:redhat:enterprise_linux:aspnetcore-runtime-dbg-8.0, p-cpe:/a:redhat:enterprise_linux:aspnetcore-targeting-pack-8.0, p-cpe:/a:redhat:enterprise_linux:cockpit-image-builder, p-cpe:/a:redhat:enterprise_linux:dotnet-apphost-pack-8.0, p-cpe:/a:redhat:enterprise_linux:dotnet-host, p-cpe:/a:redhat:enterprise_linux:dotnet-hostfxr-8.0, p-cpe:/a:redhat:enterprise_linux:dotnet-runtime-8.0, p-cpe:/a:redhat:enterprise_linux:dotnet-runtime-dbg-8.0, p-cpe:/a:redhat:enterprise_linux:dotnet-sdk-8.0-source-built-artifacts, p-cpe:/a:redhat:enterprise_linux:dotnet-sdk-8.0, p-cpe:/a:redhat:enterprise_linux:dotnet-sdk-dbg-8.0, p-cpe:/a:redhat:enterprise_linux:dotnet-targeting-pack-8.0, p-cpe:/a:redhat:enterprise_linux:dotnet-templates-8.0, p-cpe:/a:redhat:enterprise_linux:dotnet8.0, p-cpe:/a:redhat:enterprise_linux:dotnet, p-cpe:/a:redhat:enterprise_linux:grafana-pcp, p-cpe:/a:redhat:enterprise_linux:grafana-selinux, p-cpe:/a:redhat:enterprise_linux:grafana, p-cpe:/a:redhat:enterprise_linux:linux-sgx, p-cpe:/a:redhat:enterprise_linux:netstandard-targeting-pack-2.1, p-cpe:/a:redhat:enterprise_linux:sgx-common, p-cpe:/a:redhat:enterprise_linux:sgx-libs, p-cpe:/a:redhat:enterprise_linux:sgx-mpa, p-cpe:/a:redhat:enterprise_linux:sgx-pccs-admin, p-cpe:/a:redhat:enterprise_linux:sgx-pccs, p-cpe:/a:redhat:enterprise_linux:sgx-pckid-tool, p-cpe:/a:redhat:enterprise_linux:tdx-qgs

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

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 9/15/2026

Reference Information

CVE: CVE-2026-86818