Linux Distros Unpatched Vulnerability : CVE-2026-3833

high Nessus Plugin ID 311257

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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 was found in gnutls. This vulnerability occurs because gnutls performs case-sensitive comparisons of `nameConstraints` labels, specifically for `dNSName` (DNS) or `rfc822Name` (email) constraints within `excludedSubtrees` or `permittedSubtrees`. A remote attacker can exploit this by crafting a leaf certificate with casing differences in the Subject Alternative Name (SAN), leading to a policy bypass where a certificate that should be rejected is instead accepted. This could result in unauthorized access or information disclosure. (CVE-2026-3833)

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: High

ID: 311257

File Name: unpatched_CVE_2026_3833.nasl

Version: 1.9

Type: Local

Agent: unix

Family: Misc.

Published: 4/30/2026

Updated: 5/20/2026

Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Azure, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.0

CVSS v2

Risk Factor: High

Base Score: 7.1

Temporal Score: 6.4

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

CVSS Score Source: CVE-2026-3833

CVSS v3

Risk Factor: High

Base Score: 7.4

Temporal Score: 7

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

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

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:11.0, cpe:/o:centos:centos:7, cpe:/o:redhat:enterprise_linux:6, cpe:/o:redhat:enterprise_linux:7, cpe:/o:redhat:enterprise_linux:8, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:20.04:-:lts, p-cpe:/a:centos:centos:gnutls, p-cpe:/a:centos:centos:gnutls-devel, p-cpe:/a:centos:centos:gnutls-utils, p-cpe:/a:centos:centos:gnutls-guile, p-cpe:/a:centos:centos:gnutls-dane, p-cpe:/a:debian:debian_linux:gnutls28, p-cpe:/a:redhat:enterprise_linux:gnutls, p-cpe:/a:redhat:enterprise_linux:gnutls-devel, p-cpe:/a:redhat:enterprise_linux:gnutls-utils, p-cpe:/a:redhat:enterprise_linux:gnutls-guile, p-cpe:/a:redhat:enterprise_linux:gnutls-dane, cpe:/o:centos:centos:8, p-cpe:/a:redhat:enterprise_linux:gnutls-c%2b%2b, p-cpe:/a:centos:centos:gnutls-c%2b%2b, cpe:/o:canonical:ubuntu_linux:22.04:-:lts, cpe:/o:redhat:enterprise_linux:9, cpe:/o:canonical:ubuntu_linux:24.04:-:lts, cpe:/o:redhat:enterprise_linux:10, p-cpe:/a:canonical:ubuntu_linux:gnutls28, p-cpe:/a:centos:centos:gnutls-fips, p-cpe:/a:redhat:enterprise_linux:gnutls-fips, cpe:/o:canonical:ubuntu_linux:25.10, cpe:/o:canonical:ubuntu_linux:26.04

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-2026-3833

Detections

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