Linux Distros Unpatched Vulnerability : CVE-2026-63633

high Nessus Plugin ID 338294

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.

- FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to 3.28.0, freerdp_dsp_decode_opus in libfreerdp/codec/dsp.c calls Stream_EnsureRemainingCapacity on context->common.buffer even though opus_decode writes decoded PCM into the caller-supplied out stream. A malicious RDP server that negotiates WAVE_FORMAT_OPUS with a client built with WITH_OPUS enabled and WITH_DSP_FFMPEG disabled can make libopus write a large decoded frame beyond the 4096-byte StreamPool_Take destination used by channels/rdpsnd/client/rdpsnd_main.c. This can corrupt the client heap, crash the client, and may permit code execution. This issue is fixed in version 3.28.0. (CVE-2026-63633)

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: 338294

File Name: unpatched_CVE_2026_63633.nasl

Version: 1.2

Type: Local

Agent: unix

Family: Misc.

Published: 8/20/2026

Updated: 8/20/2026

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: 58.18

CVSS v2

Risk Factor: High

Base Score: 9

Temporal Score: 7.7

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

CVSS Score Source: CVE-2026-63633

CVSS v3

Risk Factor: Medium

Base Score: 6.6

Temporal Score: 6.1

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

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

CVSS v4

Risk Factor: High

Base Score: 7.7

Threat Score: 5.2

Threat Vector: CVSS:4.0/E:U

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Vulnerability Information

CPE: cpe:/o:canonical:ubuntu_linux:16.04:-:lts, cpe:/o:canonical:ubuntu_linux:18.04:-:lts, 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:11.0, cpe:/o:debian:debian_linux:12.0, cpe:/o:debian:debian_linux:13.0, cpe:/o:redhat:enterprise_linux:10, p-cpe:/a:canonical:ubuntu_linux:freerdp2, p-cpe:/a:canonical:ubuntu_linux:freerdp3, p-cpe:/a:canonical:ubuntu_linux:freerdp, p-cpe:/a:debian:debian_linux:freerdp2, p-cpe:/a:debian:debian_linux:freerdp3, p-cpe:/a:redhat:enterprise_linux:freerdp-devel, p-cpe:/a:redhat:enterprise_linux:freerdp-libs, p-cpe:/a:redhat:enterprise_linux:freerdp-server, p-cpe:/a:redhat:enterprise_linux:freerdp, p-cpe:/a:redhat:enterprise_linux:libwinpr-devel, p-cpe:/a:redhat:enterprise_linux:libwinpr

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: 8/19/2026

Reference Information

CVE: CVE-2026-63633

Detections

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