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Linux Distros Unpatched Vulnerability : CVE-2026-26965

high Nessus Plugin ID 299995

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.

 - Debian Linux - freerdp2 - FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, in the RLE planar decode path, `planar_decompress_plane_rle()` writes into `pDstData` at `((nYDst+y) * nDstStep) + (4*nXDst) + nChannel` without verifying that `(nYDst+nSrcHeight)` fits in the destination height or that `(nXDst+nSrcWidth)` fits in the destination stride. When `TempFormat != DstFormat`, `pDstData` becomes `planar->pTempData` (sized for the desktop), while `nYDst` is only validated against the **surface** by `is_within_surface()`. A malicious RDP server can exploit this to perform a heap out-of-bounds write with attacker-controlled offset and pixel data on any connecting FreeRDP client. The OOB write reaches up to 132,096 bytes past the temp buffer end, and on the brk heap (desktop 128128), an adjacent `NSC_CONTEXT` struct's `decode` function pointer is overwritten with attacker-controlled pixel data control-flowrelevant corruption (function pointer overwritten) demonstrated under deterministic heap layout (`nsc->decode = 0xFF414141FF414141`). Version 3.23.0 fixes the vulnerability. freerdp3 - FreeRDP is a free implementation of the Remote Desktop Protocol. Prior to version 3.23.0, in the RLE planar decode path, `planar_decompress_plane_rle()` writes into `pDstData` at `((nYDst+y) * nDstStep) + (4*nXDst) + nChannel` without verifying that `(nYDst+nSrcHeight)` fits in the destination height or that `(nXDst+nSrcWidth)` fits in the destination stride. When `TempFormat != DstFormat`, `pDstData` becomes `planar->pTempData` (sized for the desktop), while `nYDst` is only validated against the **surface** by `is_within_surface()`. A malicious RDP server can exploit this to perform a heap out-of-bounds write with attacker-controlled offset and pixel data on any connecting FreeRDP client. The OOB write reaches up to 132,096 bytes past the temp buffer end, and on the brk heap (desktop 128128), an adjacent `NSC_CONTEXT` struct's `decode` function pointer is overwritten with attacker-controlled pixel data control-flowrelevant corruption (function pointer overwritten) demonstrated under deterministic heap layout (`nsc->decode = 0xFF414141FF414141`). Version 3.23.0 fixes the vulnerability. (CVE-2026-26965)

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://security-tracker.debian.org/tracker/CVE-2026-26965

Plugin Details

Severity: High

ID: 299995

File Name: unpatched_CVE_2026_26965.nasl

Version: 1.1

Type: local

Agent: unix

Family: Misc.

Published: 2/26/2026

Updated: 2/26/2026

Supported Sensors: Nessus Agent, Nessus

Risk Information

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5.8

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

CVSS Score Source: CVE-2026-26965

CVSS v3

Risk Factor: High

Base Score: 8

Temporal Score: 7.3

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

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

Vulnerability Information

CPE: cpe:/o:debian:debian_linux:14.0, cpe:/o:debian:debian_linux:11.0, cpe:/o:debian:debian_linux:13.0, p-cpe:/a:debian:debian_linux:freerdp2, p-cpe:/a:debian:debian_linux:freerdp3, cpe:/o:debian:debian_linux:12.0

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-2026-26965