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Linux Distros Unpatched Vulnerability : CVE-2026-33846

high Nessus Plugin ID 311252

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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 heap buffer overflow vulnerability exists in the DTLS handshake fragment reassembly logic of GnuTLS. The issue arises in merge_handshake_packet() where incoming handshake fragments are matched and merged based solely on handshake type, without validating that the message_length field remains consistent across all fragments of the same logical message. An attacker can exploit this by sending crafted DTLS fragments with conflicting message_length values, causing the implementation to allocate a buffer based on a smaller initial fragment and subsequently write beyond its bounds using larger, inconsistent fragments. Because the merge operation does not enforce proper bounds checking against the allocated buffer size, this results in an out-of-bounds write on the heap. The vulnerability is remotely exploitable without authentication via the DTLS handshake path and can lead to application crashes or potential memory corruption. (CVE-2026-33846)

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-2026-33846

https://security-tracker.debian.org/tracker/CVE-2026-33846

https://ubuntu.com/security/CVE-2026-33846

Plugin Details

Severity: High

ID: 311252

File Name: unpatched_CVE_2026_33846.nasl

Version: 1.7

Type: Local

Agent: unix

Family: Misc.

Published: 4/30/2026

Updated: 5/22/2026

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

Risk Information

VPR

Risk Factor: Medium

Score: 4.4

CVSS v2

Risk Factor: Medium

Base Score: 6.4

Temporal Score: 5.4

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

CVSS Score Source: CVE-2026-33846

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.9

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

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

Vulnerability Information

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

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

Exploit Ease: No known exploits are available

Reference Information

CVE: CVE-2026-33846