Alibaba Cloud Linux 3 : 0047: libxml2 (ALINUX3-SA-2021:0047)

high Nessus Plugin ID 236735

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-2021:0047 advisory.

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

CVE-2021-3516:
There's a flaw in libxml2's xmllint in versions before 2.9.11. An attacker who is able to submit a crafted file to be processed by xmllint could trigger a use-after-free. The greatest impact of this flaw is to confidentiality, integrity, and availability.

CVE-2021-3517:
There is a flaw in the xml entity encoding functionality of libxml2 in versions before 2.9.11. An attacker who is able to supply a crafted file to be processed by an application linked with the affected functionality of libxml2 could trigger an out-of-bounds read. The most likely impact of this flaw is to application availability, with some potential impact to confidentiality and integrity if an attacker is able to use memory information to further exploit the application.

CVE-2021-3518:
There's a flaw in libxml2 in versions before 2.9.11. An attacker who is able to submit a crafted file to be processed by an application linked with libxml2 could trigger a use-after-free. The greatest impact from this flaw is to confidentiality, integrity, and availability.

CVE-2021-3537:
A vulnerability found in libxml2 in versions before 2.9.11 shows that it did not propagate errors while parsing XML mixed content, causing a NULL dereference. If an untrusted XML document was parsed in recovery mode and post-validated, the flaw could be used to crash the application. The highest threat from this vulnerability is to system availability.

CVE-2021-3541:
A flaw was found in libxml2. Exponential entity expansion attack its possible bypassing all existing protection mechanisms and leading to denial of service.

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: High

ID: 236735

File Name: alinux3_sa_2021-0047.nasl

Version: 1.1

Type: local

Family: Alibaba Cloud Linux Local Security Checks

Published: 5/14/2025

Updated: 5/14/2025

Supported Sensors: Nessus

Risk Information

VPR

Risk Factor: Medium

Score: 6.7

CVSS v2

Risk Factor: High

Base Score: 7.5

Temporal Score: 5.9

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

CVSS Score Source: CVE-2021-3517

CVSS v3

Risk Factor: High

Base Score: 8.8

Temporal Score: 7.9

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

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

CVSS Score Source: CVE-2021-3518

Vulnerability Information

CPE: cpe:/o:alibabacloud:alibaba_cloud_linux_3, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:libxml2-devel, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:python3-libxml2, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:libxml2, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:libxml2-debuginfo, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:libxml2-static, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:python3-libxml2-debuginfo, p-cpe:/a:alibabacloud:alibaba_cloud_linux_3:libxml2-debugsource

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

Exploit Available: true

Exploit Ease: Exploits are available

Patch Publication Date: 7/14/2021

Vulnerability Publication Date: 5/14/2021

Reference Information

CVE: CVE-2021-3516, CVE-2021-3517, CVE-2021-3518, CVE-2021-3537, CVE-2021-3541

Detections

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