# CVE-2010-3962: Microsoft Internet Explorer use-after-free in CSS processing

Source: https://junglewise.ai/threats/cve-2010-3962-microsoft-internet-explorer-use-after-free-in-css-processing  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-10-06. Updated: 2026-05-15  
License: CC BY 4.0 with a link back

CVE-2010-3962 · Severity: critical · CVSS 9.3 · Exploited in the wild · Published 2025-10-06

Internet Explorer is a legacy web browser used to access the internet and internal web applications. A critical vulnerability allows an attacker to take complete control of a user's computer if they visit a malicious website. This could lead to the theft of sensitive data, installation of malware, or total disruption of business operations. Because these versions of Internet Explorer are end-of-life, users should immediately switch to a modern, supported browser.

Technologies: [Microsoft Edge](https://junglewise.ai/threats/technologies/edge), [Microsoft Internet Explorer](https://junglewise.ai/threats/technologies/internet-explorer). Vendors: [Microsoft](https://junglewise.ai/threats/vendors/microsoft).

## Quick answers

**Is CVE-2010-3962 exploited in the wild?** Yes. CVE-2010-3962 is known to be exploited in the wild, first recorded on 6 October 2025. Treat it as urgent.

**How severe is CVE-2010-3962?** Critical severity, with a CVSS score of 9.3, published 6 October 2025.

**Which products and versions are affected?** Microsoft Internet Explorer 6; Microsoft Internet Explorer 7; Microsoft Internet Explorer 8.

**Is there a fix for CVE-2010-3962?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**How is CVE-2010-3962 attacked?** It is attacked over the network, in a network appliance.

**Am I affected by CVE-2010-3962?** Check whether you run Microsoft Edge, Microsoft Internet Explorer, Microsoft Internet Explorer 6 or one of the others listed. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

A use-after-free vulnerability exists in Microsoft Internet Explorer 6, 7, and 8 due to improper handling of Cascading Style Sheets (CSS) token sequences and the 'clip' attribute. This is often referred to as an 'invalid flag reference' or uninitialized memory corruption issue. A remote attacker can exploit this by enticing a user to visit a malicious webpage, leading to arbitrary code execution in the context of the current user. The vulnerability was notably exploited in the wild as a zero-day in 2010. Microsoft released a patch under bulletin MS10-090, though the affected browser versions are now considered end-of-life.

## Affected products

- Microsoft Internet Explorer 6
- Microsoft Internet Explorer 7
- Microsoft Internet Explorer 8

## Timeline

- 2010-11-02: advisory: Microsoft released security advisory 2458511
- 2010-11-01: exploited: Exploitation in the wild reported in November 2010
- 2025-10-06: kev added: Added to CISA Known Exploited Vulnerabilities catalog

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- [Microsoft Edge privilege escalation via incorrect authorization](https://junglewise.ai/threats/cve-2026-69446-incorrect-authorization-in-microsoft-edge-chromium-based-allows)
- [Microsoft Edge use-after-free privilege elevation](https://junglewise.ai/threats/cve-2026-96203-use-after-free-in-microsoft-edge-chromium-based-allows-an)
- [Microsoft Edge heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-96199-heap-based-buffer-overflow-in-microsoft-edge-chromium-based)
- [Microsoft Edge heap-based buffer overflow](https://junglewise.ai/threats/cve-2026-96198-heap-based-buffer-overflow-in-microsoft-edge-chromium-based)