Code execution via unvalidated hyperlink navigation
Published Feb 10, 2026 · Updated Feb 10, 2026
Security feature bypass in Microsoft MSHTML Framework allows remote attackers to execute code after a user opens crafted content. The _AttemptShellExecuteForHlinkNavigate path insufficiently validates attacker-controlled target URLs before passing resources to ShellExecuteExW outside the intended browser context. Exploitation requires user interaction with malicious HTML or shortcut content and can bypass Mark of the Web, IE Enhanced Security Configuration, and the browser sandbox.
Summary
What happened
Security feature bypass in Microsoft MSHTML Framework allows remote attackers to execute code after a user opens crafted content. The _AttemptShellExecuteForHlinkNavigate path insufficiently validates attacker-controlled target URLs before passing resources to ShellExecuteExW outside the intended browser context. Exploitation requires user interaction with malicious HTML or shortcut content and can bypass Mark of the Web, IE Enhanced Security Configuration, and the browser sandbox.
The record
- CVE
- CVE-2026-21513
- Published
- Feb 10, 2026
- Updated
- Feb 10, 2026
- Vendor
- Microsoft
- Product
- Windows Server 2019
- Classifications
- CWE-693, T1204.002, T1203
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jan 30, 2026Exploitation reportedAPT28 malicious shortcut campaign
- Feb 10, 2026Exploitation reportedCISA Known Exploited Vulnerabilities entry
- Feb 10, 2026CVE publishedPublication date reported by the CVE source.
- Feb 10, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=10.0.17763.0 <10.0.17763.8389
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Akamai MSHTML hyperlink-navigation reproductionproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Reported exploitation
- APT28 malicious shortcut campaignthreat actor
- CISA Known Exploited Vulnerabilities entryknown exploited catalog
Technologies
Your stack
See the directory against your own environment.
Your stack
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