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Important Security Alert: Microsoft Internet Explorer Vulnerability

A serious security flaw affecting older versions of Microsoft Internet Explorer has been officially recognised as actively exploited by attackers. This vulnerability could allow hackers to take control of affected computers remotely, posing a significant risk to organisations still using these outdated browsers.

20 May 2026

Reference: CVE-2010-0249

1. What is being reported?

The report highlights a 'use-after-free' vulnerability in Microsoft Internet Explorer versions 6 through 8 on various older Windows systems. This means the browser mishandles certain memory operations, which attackers can exploit to run harmful code on your computer without permission.

2. What this means in plain English

If your organisation uses these older versions of Internet Explorer, attackers could potentially access your systems remotely, leading to data theft, disruption, or further malware infections. This is particularly risky because the flaw has been actively exploited in the past and is still considered a threat.

3. Could this affect a small business?

Small organisations using outdated Windows systems and Internet Explorer versions 6 to 8 are at risk. However, most modern systems and browsers are not affected. If you use current software and supported browsers, this vulnerability likely does not impact you.

4. What to do now

  • Check if any computers in your organisation are still running Internet Explorer versions 6, 7, or 8 on older Windows systems.
  • If affected, apply any available security updates or mitigations provided by Microsoft or your IT support.
  • Consider discontinuing use of these outdated browsers and switch to supported, modern browsers.
  • Follow any additional guidance from your IT provider or cloud service suppliers regarding this vulnerability.

5. Ask your IT provider

Can you confirm whether any of our systems are using vulnerable versions of Internet Explorer, and what steps are being taken to protect us from this known exploited vulnerability?

6. Bottom line

If you still use old versions of Internet Explorer, act now to protect your organisation from a serious, actively exploited security risk.

Information based on CISA KEV, NVD, and reputable security reporting.

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