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Linux Distros Unpatched Vulnerability : CVE-2026-29774

medium Nessus Plugin ID 302240

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 3.24.0, a client-side heap buffer overflow occurs in the FreeRDP client's AVC420/AVC444 YUV-to-RGB conversion path due to missing horizontal bounds validation of H.264 metablock regionRects coordinates. In yuv.c, the clamp() function (line 347) only validates top/bottom against the surface/YUV height, but never checks left/right against the surface width. When avc420_yuv_to_rgb (line 67) computes destination and source pointers using rect->left, it performs unchecked pointer arithmetic that can reach far beyond the allocated surface buffer. A malicious server sends a WIRE_TO_SURFACE_PDU_1 with AVC420 codec containing a regionRects entry where left greatly exceeds the surface width (e.g., left=60000 on a 128px surface). The H.264 bitstream decodes successfully, then yuv420_process_work_callback calls avc420_yuv_to_rgb which computes pDstPoint = pDstData + rect->top * nDstStep + rect->left * 4, writing 16-byte SSE vectors 1888+ bytes past the allocated heap region. This vulnerability is fixed in 3.24.0. (CVE-2026-29774)

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-2026-29774

https://security-tracker.debian.org/tracker/CVE-2026-29774

Plugin Details

Severity: Medium

ID: 302240

File Name: unpatched_CVE_2026_29774.nasl

Version: 1.1

Type: local

Agent: unix

Family: Misc.

Published: 3/13/2026

Updated: 3/13/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

VPR

Risk Factor: Low

Score: 2.9

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.4

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

CVSS Score Source: CVE-2026-29774

CVSS v3

Risk Factor: Medium

Base Score: 5.3

Temporal Score: 4.9

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

Temporal Vector: CVSS:3.0/E:U/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, p-cpe:/a:centos:centos:freerdp, p-cpe:/a:centos:centos:freerdp-devel, p-cpe:/a:centos:centos:freerdp-libs, p-cpe:/a:centos:centos:freerdp-plugins, p-cpe:/a:centos:centos:libwinpr, p-cpe:/a:centos:centos:libwinpr-devel, p-cpe:/a:redhat:enterprise_linux:freerdp, p-cpe:/a:redhat:enterprise_linux:freerdp-devel, p-cpe:/a:redhat:enterprise_linux:freerdp-libs, p-cpe:/a:redhat:enterprise_linux:freerdp-plugins, p-cpe:/a:redhat:enterprise_linux:libwinpr, p-cpe:/a:redhat:enterprise_linux:libwinpr-devel, cpe:/o:centos:centos:8, cpe:/o:redhat:enterprise_linux:9, cpe:/o:debian:debian_linux:12.0, cpe:/o:debian:debian_linux:13.0, p-cpe:/a:debian:debian_linux:freerdp2, cpe:/o:redhat:enterprise_linux:10, p-cpe:/a:redhat:enterprise_linux:freerdp-server, cpe:/o:debian:debian_linux:14.0, p-cpe:/a:centos:centos:freerdp-server, p-cpe:/a:debian:debian_linux:freerdp3

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: 3/13/2026

Reference Information

CVE: CVE-2026-29774