Alibaba Cloud Linux 3 : 0108: tigervnc (ALINUX3-SA-2026:0108)

critical Nessus Plugin ID 315129

Synopsis

The remote Alibaba Cloud Linux host is missing one or more security updates.

Description

The remote Alibaba Cloud Linux 3 host has packages installed that are affected by multiple vulnerabilities as referenced in the ALINUX3-SA-2026:0108 advisory.

Package updates are available for Alibaba Cloud Linux 3 that fix the following vulnerabilities:

CVE-2026-33999:
A flaw was found in the X.Org X server. This integer underflow vulnerability, specifically in the XKB compatibility map handling, allows an attacker with local or remote X11 server access to trigger a buffer read overrun. This can lead to memory-safety violations and potentially a denial of service (DoS) or other severe impacts.

CVE-2026-34001:
A flaw was found in the X.Org X server. This use-after-free vulnerability occurs in the XSYNC fence triggering logic, specifically within the miSyncTriggerFence() function. An attacker with access to the X11 server can exploit this without user interaction, leading to a server crash and potentially enabling memory corruption. This could result in a denial of service or further compromise of the system.

CVE-2026-34003:
A flaw was found in the X.Org X server's XKB key types request validation. A local attacker could send a specially crafted request to the X server, leading to an out-of-bounds memory access vulnerability. This could result in the disclosure of sensitive information or cause the server to crash, leading to a Denial of Service (DoS). In certain configurations, higher impact outcomes may be possible.

CVE-2026-34352:
In TigerVNC before 1.16.2, Image.cxx in x0vncserver allows other users to observe or manipulate the screen contents, or cause an application crash, because of incorrect permissions.

Tenable has extracted the preceding description block directly from the Alibaba Cloud Linux security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

Solution

Update the affected packages.

Plugin Details

Severity: Critical

ID: 315129

File Name: alinux3_sa_2026-0108.nasl

Version: 1.1

Type: Local

Family: Alibaba Cloud Linux Local Security Checks

Published: 5/18/2026

Updated: 5/18/2026

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: Critical

Base Score: 10

Temporal Score: 7.4

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

CVSS Score Source: CVE-2026-34352

CVSS v3

Risk Factor: Critical

Base Score: 9.8

Temporal Score: 8.5

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

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

Vulnerability Information

CPE: p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:tigervnc-license, cpe:/o:alibabacloud:alibaba_cloud_linux_3, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:tigervnc, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:tigervnc-server-minimal, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:tigervnc-selinux, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:tigervnc-server-module, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:tigervnc-icons, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:tigervnc-server

Required KB Items: Host/local_checks_enabled, Host/Alibaba/release, Host/Alibaba/rpm-list, Host/cpu

Exploit Ease: No known exploits are available

Patch Publication Date: 5/13/2026

Vulnerability Publication Date: 3/26/2026

Reference Information

CVE: CVE-2026-33999, CVE-2026-34001, CVE-2026-34003, CVE-2026-34352

Detections

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