Amazon Linux 2 : tigervnc (ALAS-2025-2917)

high Nessus Plugin ID 241768

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Synopsis

The remote Amazon Linux 2 host is missing a security update.

Description

The version of tigervnc installed on the remote host is prior to 1.8.0-24. It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2-2025-2917 advisory.

A flaw was found in the X Rendering extension's handling of animated cursors. If a client provides no cursors, the server assumes at least one is present, leading to an out-of-bounds read and potential crash.
(CVE-2025-49175)

A flaw was found in the Big Requests extension. The request length is multiplied by 4 before checking against the maximum allowed size, potentially causing an integer overflow and bypassing the size check.
(CVE-2025-49176)

A flaw was found in the X server's request handling. Non-zero 'bytes to ignore' in a client's request can cause the server to skip processing another client's request, potentially leading to a denial of service.
(CVE-2025-49178)

The RecordSanityCheckRegisterClients() function in the X Record extension implementation of the Xserver checks for the request length, but does not check for integer overflow.

A client might send a very large value for either the number of clients or the number of protocol ranges that will cause an integer overflow in the request length computation, defeating the check for request length. (CVE-2025-49179)

A flaw was found in the RandR extension, where the RRChangeProviderProperty function does not properly validate input. This issue leads to an integer overflow when computing the total size to allocate.
(CVE-2025-49180)

Tenable has extracted the preceding description block directly from the tested product 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

Run 'yum update tigervnc' to update your system.

Plugin Details

Severity: High

ID: 241768

File Name: al2_ALAS-2025-2917.nasl

Version: 1.1

Type: local

Agent: unix

Family: Amazon Linux Local Security Checks

Published: 7/10/2025

Updated: 7/10/2025

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

Risk Information

VPR

Risk Factor: High

Score: 7.4

CVSS v2

Risk Factor: Medium

Base Score: 6.8

Temporal Score: 5

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

CVSS Score Source: CVE-2025-49180

CVSS v3

Risk Factor: High

Base Score: 7.8

Temporal Score: 6.8

Vector: CVSS:3.0/AV:L/AC:L/PR:L/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:amazon:linux:tigervnc-icons, p-cpe:/a:amazon:linux:tigervnc-server-module, p-cpe:/a:amazon:linux:tigervnc-debuginfo, p-cpe:/a:amazon:linux:tigervnc, p-cpe:/a:amazon:linux:tigervnc-server-applet, p-cpe:/a:amazon:linux:tigervnc-server-minimal, cpe:/o:amazon:linux:2, p-cpe:/a:amazon:linux:tigervnc-server, p-cpe:/a:amazon:linux:tigervnc-license

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

Exploit Ease: No known exploits are available

Patch Publication Date: 7/10/2025

Vulnerability Publication Date: 6/17/2025

Reference Information

CVE: CVE-2025-49175, CVE-2025-49176, CVE-2025-49178, CVE-2025-49179, CVE-2025-49180

Detections

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