Microsoft Internet Explorer Use-After-Free Vulnerability - Active in CISA KEV catalog.
Description
Microsoft Internet Explorer Use-After-Free Vulnerability - Active in CISA KEV catalog.
AI Analyst Comment
Remediation
FEDERAL DEADLINE: June 2, 2026 (13 days). Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable. FEDERAL DEADLINE: June 2, 2026 (13 days). Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA KEV Details
Deadline: June 2, 2026
Required Action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
---METADATA---
VENDOR: Microsoft
PRODUCT: Internet Explorer
AFFECTED_VERSIONS: Microsoft Internet Explorer 6, 6 SP1, 7, and 8 on various Windows versions (see description)
CONFIDENCE: high
MISSING: none
---END_METADATA---
Description Summary:
A use-after-free vulnerability in the Microsoft Internet Explorer HTML rendering engine allows remote attackers to execute arbitrary code.
Executive Summary:
This critical memory corruption vulnerability in Microsoft Internet Explorer is confirmed to be actively exploited in the wild and enables remote code execution.
Vulnerability Details
CVE-ID: CVE-2010-0249
Affected Software: Microsoft Internet Explorer
Affected Versions: Microsoft Internet Explorer 6, 6 SP1, 7, and 8 on Windows 2000 SP4; Windows XP SP2/SP3; Windows Server 2003 SP2; Windows Vista; Windows Server 2008; and Windows 7.
Vulnerability: This is a use-after-free vulnerability involving memory corruption in the HTML object handling process. An unauthenticated attacker can exploit this by directing a user to a malicious website, resulting in the execution of arbitrary code.
Business Impact
With a CVSS score of 9.5, the risk of remote code execution is extreme. Exploitation of this flaw allows attackers to bypass security boundaries, potentially leading to full system takeover, data exfiltration, or the deployment of ransomware. The historical use of this vulnerability in sophisticated campaigns like "Operation Aurora" underscores its effectiveness as an initial access vector.
Remediation Plan
Immediate Action: Apply the patch associated with MS10-002. Organizations should phase out the use of Internet Explorer entirely in favor of modern, secure browsers.
Proactive Monitoring: Scan for unauthorized execution of child processes spawned by the browser process and monitor for anomalous outbound network connections.
Compensating Controls: Deploy endpoint protection tools configured to block known browser-based exploits and restrict browser access to untrusted external sites via strict proxy policies.
Exploitation Status
Public Exploit Available: Yes — weaponized modules exist in both Metasploit and ExploitDB.
Analyst Notes: This vulnerability is confirmed to be actively exploited in the wild as of December 2009/January 2010. It remains a high-risk item due to its inclusion in the CISA KEV catalog and the availability of weaponized exploits.
Analyst Recommendation
Given the severity of this vulnerability and its history of use in advanced persistent threat campaigns, immediate remediation is mandatory for any remaining legacy systems. Users must transition to supported browsers that receive regular security updates and feature modern memory protection mechanisms.