CVE-2010-0806 is an use-after-free vulnerability in Microsoft Internet Explorer. CISA added it to the Known Exploited Vulnerabilities catalogue on 20 May 2026, which means attackers have used it in real attacks. The impacted product could be end-of-life (EoL) and/or end-of-service (EoS). Users should discontinue product utilization.
What the vulnerability means in practice
A use-after-free in Internet Explorer means the browser continues to use memory after it has been released, which can corrupt execution flow and, in exploited cases, let an attacker run code in the browser process. That makes the weakness dangerous anywhere the browser is still reachable, especially on unsupported or end-of-life systems.
This CVE should be understood as an actively exploited browser-memory weakness, not just a theoretical coding flaw. For record details and authoritative vulnerability metadata, use the CVE Program entry and the NIST National Vulnerability Database record rather than relying on secondary summaries.
How exposure is usually assessed
Exposure starts with knowing whether Internet Explorer is present at all, because many organisations still have legacy images, embedded dependencies, or compatibility-mode workflows that keep it reachable long after it is no longer intended for daily use. Inventory should cover endpoints, virtual desktops, kiosk systems, and any business process that can still invoke the browser engine.
Internet-facing exposure matters because browser exploits are often delivered through malicious links, drive-by content, or compromised sites. If a system can browse untrusted web content and still runs the affected software, the organisation should assume the attack surface is materially larger than its standard desktop baseline.
For exploit-priority context and patch status, cross-check vendor guidance with the CISA KEV catalogue, then align that information with your own asset inventory and exception records. The NIST Cybersecurity Framework 2.0 is useful here as a governance lens for identifying, protecting, detecting, responding, and recovering around a known exploited weakness.
Remediation and compensating controls
The best remediation is to remove the vulnerable browser from service, because the primary definition indicates the product may be end-of-life or end-of-service. Where immediate removal is not yet possible, organisations should reduce use of the browser, restrict access to trusted sites only, and isolate systems that still depend on it.
Compensating controls should focus on limiting exploit delivery and limiting blast radius. That usually means tighter web filtering, application allowlisting, stronger endpoint containment, and rapid retirement of systems that cannot be updated or replaced. When a legacy browser must remain temporarily available, treat it as a temporary exception with an expiry date, not a stable operating state.
Browser weakness management also benefits from a vulnerability programme that prioritises known exploited items first. Vulnerability Management Guide is a useful companion for understanding how KEV-driven prioritisation, exception handling, and remediation verification fit together.
Detection and post-exploitation review
Because use-after-free exploitation often targets code execution, defenders should review endpoint telemetry, browser crash patterns, suspicious child processes, script activity, and unexpected downloads or follow-on payloads. A clean patch does not prove a system was never compromised, especially if exploitation occurred before remediation.
Post-patch review should ask whether the browser was used to drop malware, steal session data, or stage persistence elsewhere on the host. Review authentication logs, browser caches, download history, and endpoint detection alerts for signs that the exploit was only the initial access step.
For broader attack-path context, MITRE ATT&CK Enterprise Matrix helps map browser exploitation to credential access, execution, persistence, and lateral movement patterns that may follow initial compromise.
Risk and Threat Considerations
Browser use-after-free vulnerabilities are attractive because they sit at the intersection of user interaction and code execution, which makes them effective for initial compromise at scale. The danger increases when the affected browser is legacy or unsupported, because defenders may be unable to patch quickly enough to close the exposure window.
Failure mechanism: An attacker triggers memory corruption through crafted content or a malicious page, then leverages the corrupted state to execute code in the browser process.
Impact: Successful exploitation can lead to malware installation, session theft, data access, or a foothold for broader endpoint compromise.
Standards & Framework Alignment
This section maps relevant standards and security frameworks to the operational risks and controls described in this guidance.
CIS Controls v8 and NIST CSF 2.0 set the governance and control requirements practitioners need to meet.
| Framework | Control / Reference | Relevance |
|---|---|---|
| CIS Controls v8 | CIS-7 — Continuous Vulnerability Management | Use KEV priority and exposure tracking to find systems still running the browser. |
| Recommendation — Prioritise, patch, or remove the exposed browser using continuous vulnerability management. | ||
| NIST CSF 2.0 | GV.RM-01 — Risk Management Strategy | Known exploited browser CVEs require prioritisation and exception governance. |
| PR.IP-?? — N/A | Omitted, not a valid CSF 2.0 control reference. | |
| Recommendation — Treat KEV-listed browser flaws as priority risks in the organisation's risk strategy. Omitted. | ||
Practitioner Guidance
Why practitioners should care: This kind of CVE is not just a patching issue, it is an exposure-management issue. If the affected browser is still installed, the organisation should assume that any untrusted browsing path can become an entry point until the software is removed or tightly contained.
What to watch for: Prioritise systems that are both internet-reachable and still dependent on legacy browser behaviour, then confirm whether users, scripts, or embedded applications can still invoke the vulnerable product. If they can, treat the system as high-priority for retirement or isolation.
Practitioner takeaway: For actively exploited browser flaws, remediation is strongest when it combines removal, containment, and post-exploitation review rather than relying on patching alone.