Actively Exploited — CISA KEV

CVE-2010-3962: Microsoft Internet Explorer High-Severity Vulnerability

Severity: High | CVSS 3.1: 8.1 | Published: 2010-11-05 | KEV Added: 2025-10-06

What is CVE-2010-3962?

Use-after-free vulnerability in Microsoft Internet Explorer 6, 7, and 8 allows remote attackers to execute arbitrary code via vectors related to Cascading Style Sheets (CSS) token sequences and the clip attribute, aka an "invalid flag reference" issue or "Uninitialized Memory Corruption Vulnerability," as exploited in the wild in November 2010.

Technical Analysis

Weakness Classification

This vulnerability is classified as CWE-416 — Use After Free. The software accesses memory after it has been freed, which can lead to crashes, data corruption, or arbitrary code execution.

Attack Vector Breakdown

  • Attack Vector: Network
  • Attack Complexity: High
  • Privileges Required: None
  • User Interaction: None
  • Scope: Unchanged
  • Confidentiality: High
  • Integrity: High
  • Availability: High

Impact Analysis

This vulnerability is exploitable over the network, meaning any system reachable via the internet or internal network is potentially at risk without physical access. Successful exploitation can result in full confidentiality breach (complete data disclosure), complete integrity compromise (data modification or code execution), total availability loss (denial of service). The software accesses memory after it has been freed, which can lead to crashes, data corruption, or arbitrary code execution.

Exploitation Probability (EPSS): 89.7% chance of exploitation in the next 30 days (100th percentile). This places the vulnerability in the highest risk tier — immediate action is critical.

Is CVE-2010-3962 being exploited?

Yes. CVE-2010-3962 is listed in CISA's Known Exploited Vulnerabilities (KEV) catalog, restricted to CVEs with confirmed active exploitation in the wild. CISA added this vulnerability on 2025-10-06. Inclusion in KEV triggers the patching mandate under BOD 22-01 for U.S. federal civilian agencies, with a remediation deadline of 2025-10-27.

How to fix CVE-2010-3962

Apply the latest security update via Windows Update, WSUS, or Microsoft Update Catalog. For enterprise environments, use SCCM/Intune for managed deployment. If the patch cannot be applied immediately, check the MSRC advisory for workarounds such as registry-based mitigations or disabling affected features. Check the Microsoft Security Response Center page for the specific patch or update. CISA's Known Exploited Vulnerabilities catalog requires U.S. federal agencies to remediate this vulnerability by the due date shown below under Binding Operational Directive 22-01. Private organizations should treat KEV entries as priority-one patches because active exploitation has been confirmed in the wild.

Related Vulnerabilities

Other actively exploited vulnerabilities affecting Internet Explorer or sharing the same weakness (CWE-416):

  • CVE-2010-0249 (High 8.8) [same product + same CWE] — Use-after-free vulnerability in Microsoft Internet Explorer 6, 6 SP1, 7, and 8…
  • CVE-2013-3893 (High 8.8) [same product + same CWE] — Use-after-free vulnerability in the SetMouseCapture implementation in…
  • CVE-2010-0806 (High 8.8) [same product] — Use-after-free vulnerability in the Peer Objects component (aka iepeers.dll)…
  • CVE-2025-62221 (High 7.8) [same vendor + same CWE] — Use after free in Windows Cloud Files Mini Filter Driver allows an authorized…
  • CVE-2025-32709 (High 7.8) [same vendor + same CWE] — Null pointer dereference in Windows Ancillary Function Driver for WinSock…

Frequently asked questions

Is CVE-2010-3962 critical?

CVE-2010-3962 has a CVSS 3.1 base score of 8.1 — High severity. It should be treated as a priority patch, especially given the active exploitation confirmed by CISA.

Is CVE-2010-3962 being actively exploited?

Yes — CISA added CVE-2010-3962 to the Known Exploited Vulnerabilities catalog on 2025-10-06. Inclusion in KEV means CISA has confirmed in-the-wild exploitation.

How do I patch CVE-2010-3962?

Apply the security update from Microsoft for Internet Explorer. Federal agencies must remediate by 2025-10-27 under BOD 22-01. Refer to the Microsoft Security Response Center for the official patch.

What type of vulnerability is CVE-2010-3962?

CVE-2010-3962 is classified under CWE-416 (Use After Free). The software accesses memory after it has been freed, which can lead to crashes, data corruption, or arbitrary code execution.

What is the CVSS score for CVE-2010-3962?

CVE-2010-3962 has a CVSS 3.1 base score of 8.1, classifying it as High severity. The attack vector is Network, attack complexity is High, and no privileges are required.