What is the CVSS score of CVE-2021-3516?

CVE-2021-3516 has a CVSS 3.1 base score of 7.8 (High). CVSS vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. EPSS exploitation probability: 2.0%.

Is there a public PoC exploit available for CVE-2021-3516?

Yes, a public proof-of-concept exploit is available for CVE-2021-3516. Prioritise patching immediately. EPSS: 2.0%.

Is there a patch available for CVE-2021-3516?

Yes, a patch is available for CVE-2021-3516. Update the affected software to the latest version immediately.

Xmllint CVE-2021-3516

HIGH

Use After Free (CWE-416)

2021-06-01 secalert@redhat.com

Information Disclosure Use After Free Memory Corruption Debian Oracle Red Hat Debian Linux Enterprise Linux Fedora Jboss Core Services Ontap Select Deploy Administration Utility Clustered Data Ontap Clustered Data Ontap Antivirus Connector Zfs Storage Appliance Kit Xmllint Netapp Xmlsoft Fedoraproject

7.8

CVSS 3.1 · NVD

View

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 7.8 (HIGH). Attack characteristics: local attack vector, low complexity, no privileges required, user interaction required. Public proof-of-concept exploit code is available.
Exploit ScenarioDerived	A local attacker with access to the system could access freed memory to execute arbitrary code or crash the 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 2.0% exploitation probability (EPSS)

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AnalysisAI

There's a flaw in libxml2's xmllint in versions before 2.9.11. Rated high severity (CVSS 7.8), this vulnerability is no authentication required, low attack complexity. Public exploit code available.

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.

Affects your stack

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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'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. Affected products include: Xmlsoft Xmllint, Debian Debian Linux, Fedoraproject Fedora, Redhat Jboss Core Services, Redhat Enterprise Linux. Version information: before 2.9.11..

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Severity by source

NVD PRIMARY 7.8 HIGH

AV:L/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

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

DescriptionNVD

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.

Threat Intelligence Overview

EPSS Score

2.0%

Top 22% exploitable

Exploit

POC

Public exploit code exists

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 Yes

EPSS 2.0%

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

Poc

System Exposure· derived

Small

Automatable· derived

Human Impact· derived

Medium

Priority Score

Low Medium High Critical

KEV: 0

EPSS: +2

CVSS: +39

PoC: +20

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.