What is the CVSS score of CVE-2021-3518?

CVE-2021-3518 has a CVSS 3.1 base score of 8.8 (High). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. EPSS exploitation probability: 3.7%.

Is there a patch available for CVE-2021-3518?

Yes, a patch is available for CVE-2021-3518. Update the affected software to the latest version immediately.

Libxml2 CVE-2021-3518

HIGH

Use After Free (CWE-416)

2021-05-18 secalert@redhat.com

Information Disclosure Use After Free Memory Corruption Debian Oracle Red Hat Active Iq Unified Manager Debian Linux Enterprise Linux Fedora Jboss Core Services Libxml2 Peoplesoft Enterprise Peopletools Ontap Select Deploy Administration Utility Manageability Software Development Kit Clustered Data Ontap Hci H410C Firmware Enterprise Manager Ops Center Clustered Data Ontap Antivirus Connector Mysql Workbench Communications Cloud Native Core Network Function Cloud Native Environment Enterprise Manager Base Platform Snapdrive Real User Experience Insight Netapp Xmlsoft Fedoraproject

8.8

CVSS 3.1 · NVD

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Vulnerability Assessment

Weakness	CWE CWE-416 ASVS 5.0 V15 - Secure Coding and Architecture Memory lifecycle management MITRE ATT&CK 2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 8.8 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required.
Exploit ScenarioDerived	A remote attacker could access freed memory to execute arbitrary code or crash the application by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).

Patch available 3.7% exploitation probability (EPSS)

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AnalysisAI

There's a flaw in libxml2 in versions before 2.9.11. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. This Use After Free vulnerability could allow attackers to access freed memory to execute arbitrary code or crash the application.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Use smart pointers or garbage-collected languages. Set pointers to NULL after freeing. Enable memory sanitizers.

Affected Packages

rubygems nokogiri fix: 1.11.4

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in rubygems

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified as Use After Free (CWE-416), which allows attackers to access freed memory to execute arbitrary code or crash the application. 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. Affected products include: Xmlsoft Libxml2, Debian Debian Linux, Redhat Jboss Core Services, Redhat Enterprise Linux, Fedoraproject Fedora. Version information: before 2.9.11..

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 8.8 HIGH

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

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionNVD

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.

Threat Intelligence Overview

EPSS Score

3.7%

Top 12% exploitable

Data Quality

3 sources

Confidence: Low

NVD

CVE.org

EPSS

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue

Severity HIGH

CISA KEV No

Public POC No

EPSS 3.7%

Patch available Yes

Active threat No

Deciding rule

HIGH severity (CVSS 7.0-8.9)

What every action level means

Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.

Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.

This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.

This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.

Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived

Scheduled

Exploitation· derived

None

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +4

CVSS: +44

PoC: 0

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Use After Free HIGH

Use-after-free vulnerabilities occur when a program continues to access memory through a pointer after that memory has been deallocated.

Memory Corruption HIGH

Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.

Information Disclosure MEDIUM

Information disclosure occurs when an application unintentionally exposes sensitive data that aids attackers in reconnaissance or directly compromises security.

Affected Products (CPE)NVD

cpe:2.3:a:xmlsoft:libxml2:*:*:*:*:*:*:*:*

cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

cpe:2.3:a:redhat:jboss_core_services:-:*:*:*:*:*:*:*

cpe:2.3:o:redhat:enterprise_linux:8.0:*:*:*:*:*:*:*

cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*

cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*

cpe:2.3:a:netapp:active_iq_unified_manager:-:*:*:*:*:vmware_vsphere:*:*

cpe:2.3:a:netapp:clustered_data_ontap:-:*:*:*:*:*:*:*

cpe:2.3:a:netapp:clustered_data_ontap_antivirus_connector:-:*:*:*:*:*:*:*

cpe:2.3:a:netapp:manageability_software_development_kit:-:*:*:*:*:*:*:*

cpe:2.3:a:netapp:ontap_select_deploy_administration_utility:-:*:*:*:*:*:*:*

cpe:2.3:a:netapp:snapdrive:-:*:*:*:*:windows:*:*

cpe:2.3:o:netapp:hci_h410c_firmware:-:*:*:*:*:*:*:*

cpe:2.3:a:oracle:communications_cloud_native_core_network_function_cloud_native_environment:1.10.0:*:*:*:*:*:*:*

cpe:2.3:a:oracle:enterprise_manager_base_platform:13.4.0.0:*:*:*:*:*:*:*

cpe:2.3:a:oracle:enterprise_manager_base_platform:13.5.0.0:*:*:*:*:*:*:*

cpe:2.3:a:oracle:enterprise_manager_ops_center:12.4.0.0:*:*:*:*:*:*:*

cpe:2.3:a:oracle:mysql_workbench:*:*:*:*:*:*:*:*

cpe:2.3:a:oracle:peoplesoft_enterprise_peopletools:8.58:*:*:*:*:*:*:*

cpe:2.3:a:oracle:real_user_experience_insight:13.4.1.0:*:*:*:*:*:*:*

+ 1 more

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Same weakness CWE-416 – Use After Free

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References

Advisories & patches

PATCH https://bugzilla.redhat.com/show_bug.cgi?id=1954242 PATCH https://www.oracle.com/security-alerts/cpuapr2022.html PATCH https://www.oracle.com/security-alerts/cpuoct2021.html REF http://seclists.org/fulldisclosure/2021/Jul/54 REF http://seclists.org/fulldisclosure/2021/Jul/55 REF http://seclists.org/fulldisclosure/2021/Jul/58 REF http://seclists.org/fulldisclosure/2021/Jul/59 REF https://cert-portal.siemens.com/productcert/html/ssa-398330.html REF https://lists.apache.org/thread.html/r58af02e294bd07f487e2c64ffc0a29b837db5600e33b6e698b9d696b%40%3Cissues.bookkeeper.apache.org%3E REF https://lists.apache.org/thread.html/rf4c02775860db415b4955778a131c2795223f61cb8c6a450893651e4%40%3Cissues.bookkeeper.apache.org%3E REF https://lists.debian.org/debian-lts-announce/2021/05/msg00008.html REF https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/BZOMV5J4PMZAORVT64BKLV6YIZAFDGX6/ REF https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/QVM4UJ3376I6ZVOYMHBNX4GY3NIV52WV/ REF https://security.gentoo.org/glsa/202107-05 REF https://security.netapp.com/advisory/ntap-20210625-0002/ REF https://support.apple.com/kb/HT212601 REF https://support.apple.com/kb/HT212602 REF https://support.apple.com/kb/HT212604 REF https://support.apple.com/kb/HT212605 REF https://www.oracle.com/security-alerts/cpujul2022.html

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