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CVE-2012-4787

Critical Vulnerability: CVE-2012-4787 — microsoft — internet_explorer, windows_7

Use-after-free vulnerability in Microsoft Internet Explorer 9 and 10 allows remote attackers to execute arbitrary code via a crafted web site that triggers access to an object that (1) was not properly initialized or (2) is deleted, aka "Improper Ref Counting Use After Free Vulnerability."

Thursday, May 14, 2026microsoftVulnios Threat Intelligence
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Vulnerability Snapshot

CVE-2012-4787 is rated CRITICAL — exploitation is trivial or already observed in the wild and impact is severe. Patch immediately, not on the next maintenance window.

Affected technology: internet_explorer, windows_7, windows_server_2008, windows_vista, windows_8, plus 2 other product variants.

Executive Summary

Use-after-free vulnerability in Microsoft Internet Explorer 9 and 10 allows remote attackers to execute arbitrary code via a crafted web site that triggers access to an object that (1) was not properly initialized or (2) is deleted, aka "Improper Ref Counting Use After Free Vulnerability."

Why It Matters

CVE-2012-4787 is rated CRITICAL severity, requiring immediate attention from security teams.

CVSS Base Score: 9/10

Affected Technologies

Vendors: microsoft

Products: internet_explorer, windows_7, windows_server_2008, windows_vista, windows_8, windows_rt, windows_server_2012

🛡️What Defenders Should Check

  • Check if you are affected — Review your asset inventory for products listed in CVE-2012-4787.
  • Apply available patches — Visit vendor advisories for the latest security updates.
  • Monitor for exploitation — Check your SIEM/IDS logs for related indicators.

    • Use Vulnios to continuously monitor your exposure to CVE-2012-4787 and similar vulnerabilities.

    References & Sources

  • http://www.us-cert.gov/cas/techalerts/TA12-346A.html
  • https://docs.microsoft.com/en-us/security-updates/securitybulletins/2012/ms12-077
  • https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16211
  • http://www.us-cert.gov/cas/techalerts/TA12-346A.html
  • https://docs.microsoft.com/en-us/security-updates/securitybulletins/2012/ms12-077
  • https://oval.cisecurity.org/repository/search/definition/oval%3Aorg.mitre.oval%3Adef%3A16211

    • How Vulnios Detects This

    Vulnios scans for this vulnerability using KEV cross-check that flags any host where this CVE is already on CISA's exploited list. Run a scan against your environment to see whether you are exposed; findings are linked back to the original CVE record so triage starts with the patch path already known.

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    Affected Products

    internet_explorerwindows_7windows_server_2008windows_vistawindows_8windows_rtwindows_server_2012

    Sources

    Related Threat Alerts

    Frequently Asked Questions

    What is CVE-2012-4787?

    CVE-2012-4787 is a critical-severity vulnerability tracked under the Common Vulnerabilities and Exposures program. Use-after-free vulnerability in Microsoft Internet Explorer 9 and 10 allows remote attackers to execute arbitrary code via a crafted web site that triggers access to an object that (1) was not properl

    Am I affected?

    Check whether your environment runs internet_explorer, windows_7, windows_server_2008, windows_vista, windows_8. If you operate any of those, treat yourself as in scope until you have evidence otherwise. A Vulnios scan will identify the exact assets carrying the affected version.

    How urgent is the response?

    Critical: do not wait for your normal patch cycle. Verify exposure today, apply the vendor patch immediately, and add detection rules for any post-exploit indicators.

    How do I remediate?

    Apply the vendor patch listed in the upstream advisory linked under Sources. If the patch is not yet available, follow the vendor-supplied workaround (often a config flag or feature disable) and add detections for the published exploit pattern in your SIEM. Re-scan after the patch lands to confirm the finding clears.

    Where can I track exploitation activity?

    Watch CISA's Known Exploited Vulnerabilities catalog for CVE-2012-4787. Cross-reference with public exploit databases and your own SIEM/IDS for indicator-of-compromise patterns. Vulnios tracks KEV status automatically and surfaces it on the asset findings view.

    How does Vulnios help with this?

    Vulnios continuously cross-references your asset inventory against the live CVE feed (NVD, vendor advisories, CISA KEV, and curated OSINT). When a new CVE matches your environment, you get a prioritized finding with the severity, KEV status, exploit-prediction (EPSS), and a direct path to the vendor patch. You can start a free scan from the homepage.

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