What is the CVSS score of CVE-2014-1776?

CVE-2014-1776 has a CVSS 3.1 base score of 9.8 (Critical). CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. EPSS exploitation probability: 80.2%.

Is there a public PoC exploit available for CVE-2014-1776?

Yes, a public proof-of-concept exploit is available for CVE-2014-1776. Prioritise patching immediately. EPSS: 80.2%.

How to fix or mitigate CVE-2014-1776?

Within 24 hours: Identify all affected systems running Microsoft Internet Explorer 6 and apply vendor patches immediately. If patching is delayed, consider network segmentation to limit exposure.

Microsoft CVE-2014-1776

CRITICAL

Use After Free (CWE-416)

2014-04-27 secure@microsoft.com

RCE Buffer Overflow Denial Of Service Use After Free Memory Corruption Microsoft

9.8

CVSS 3.1 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-416 OWASP Top 10:2025 A06:2021 - Vulnerable and Outdated Components ASVS 5.0 V14 - Configuration Dependency management, component inventory MITRE ATT&CK 2 techniques across 2 tactics: Execution, Privilege Escalation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	Critical risk (CVSS 9.8). This zero-day affected every supported IE version simultaneously, a rarity that indicated a deep, fundamental flaw. Active exploitation in April 2014 prompted an emergency out-of-band patch, including for Windows XP despite its end-of-support.
Exploit ScenarioDerived	A sophisticated APT campaign used a compromised website to deliver the IE zero-day. The exploit targeted users across IE 6-11, using version-specific exploitation techniques. The payload was a multi-stage implant with data exfiltration capabilities.

Act Now Prioritize within 24-48h. Why: In CISA KEV with patch available.

Exploited in the wild (CISA KEV) Patch available 80.2% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 26, 2026

Internet Explorer 6 through 11 contain a use-after-free vulnerability in CMarkup::IsConnectedToPrimaryMarkup that allows remote code execution, exploited as a zero-day in April 2014 with initial attribution to APT groups.

Earlier versions of this analysis (1)

v1 Mar 26, 2026 - 11:18 CVSS 9.8

A critical use-after-free vulnerability affecting all supported versions of Internet Explorer (6-11) enables remote code execution through memory corruption. Originally associated with VGX.DLL, Microsoft clarified the root cause is in CMarkup processing.

RemediationAI

Migrate to modern browsers. This vulnerability's severity prompted Microsoft to issue a rare patch for end-of-life Windows XP. Apply MS14-021.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

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

Technical ContextAI · show details

The CWE-416 use-after-free in the CMarkup::IsConnectedToPrimaryMarkup function is triggered when JavaScript manipulates the DOM to free a CMarkup object while IE still holds references to it. The vulnerability initially appeared to involve VGX.DLL (VML rendering) but was ultimately traced to the core HTML rendering engine.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.8 CRITICAL

AV:N/AC:L/PR:N/UI:N/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

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Lifecycle Timeline

Added to CISA KEV

Oct 22, 2025 - 01:15 cisa

CISA KEV

PoC Detected

Oct 22, 2025 - 01:15 vuln.today

Public exploit code

Patch released

Oct 22, 2025 - 01:15 nvd

Patch available

CVE Published

Apr 27, 2014 - 10:55 nvd

CRITICAL 9.8

DescriptionCVE.org

Use-after-free vulnerability in Microsoft Internet Explorer 6 through 11 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via vectors related to the CMarkup::IsConnectedToPrimaryMarkup function, as exploited in the wild in April 2014. NOTE: this issue originally emphasized VGX.DLL, but Microsoft clarified that "VGX.DLL does not contain the vulnerable code leveraged in this exploit. Disabling VGX.DLL is an exploit-specific workaround that provides an immediate, effective workaround to help block known attacks."

Executive ViewAI

Why It Matters

Organizations using Microsoft Internet Explorer 6 face critical risk from CVE-2014-1776, a use-after-free vulnerability rated CVSS 9.8. Successful exploitation could critically impact the confidentiality, integrity, and availability of affected systems. This vulnerability is actively exploited in the wild (KEV-listed) and requires immediate remediation. A patch is available and should be applied immediately given the critical severity.

Business Impact: Severe

Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Enable ASLR and DEP where available; (2) Implement network segmentation; (3) Monitor for exploitation indicators.

Threat Intelligence Overview

Threat Score

9.4/10

Composite threat intelligence

EPSS Score

80.2%

Top 1% exploitable

Threat Intel

1 source

Exploit

POC

Public exploit code exists

Data Quality

5 sources

Confidence: Medium

NVD

CVE.org

CISA KEV

EPSS THREAT

VulDB

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 CRITICAL

CISA KEV Yes

Public POC Yes

EPSS 80.2%

Patch available Yes

Active threat Yes

Deciding rule

In CISA KEV with patch available

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

Immediate

Exploitation· derived

Active

System Exposure· derived

Open

Automatable· derived

Yes

Human Impact

Very High

Priority Score

209

Low Medium High Critical

KEV: +50

EPSS: +80

CVSS: +49

PoC: +20

Weaponized: 0

Threat intel: +10

Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

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.

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

Denial of Service MEDIUM

Denial of Service attacks render applications or systems unavailable by overwhelming resources or triggering failure conditions.