CVE-2024-29988: Microsoft Windows SmartScreen Prompt Security Feature Bypass

Automated analysis

Generated by VULONE's analysis model from the NVD record, CISA KEV and EPSS data on 17 September 2026. Confidence: high.

high priorityThe flaw is confirmed exploited in the wild per CISA KEV, has a high CVSS score of 8.8, and affects a broad set of widely deployed Windows versions, though it requires user interaction.

What it is

CVE-2024-29988 is a security feature bypass in the Microsoft Windows SmartScreen prompt. An attacker can craft a file or content that evades the SmartScreen warning, so users are not shown the usual reputation-based prompt before opening it. Because SmartScreen is a key last line of defense against untrusted downloads, bypassing it makes malware delivery significantly easier.

Impact

An attacker can get a victim to open a malicious file or link without the expected SmartScreen warning, enabling code execution in the user's context. The CVSS vector indicates high confidentiality, integrity, and availability impact once the bypass is used to deliver a payload.

Attack surface

The vulnerability is network-reachable (AV:N) with no privileges required (PR:N), but exploitation requires user interaction (UI:R) because the victim must open or interact with the crafted content. No authentication is needed to trigger the bypass.

Exploitation

CISA added this CVE to the Known Exploited Vulnerabilities catalog on 2024-04-30, confirming active exploitation in the wild. EPSS estimates a 44.9% probability of exploitation in the next 30 days (98.7th percentile), and Microsoft has published a patch.

What to do

• Apply the Microsoft security update for CVE-2024-29988 on all affected Windows 10, Windows 11, and Windows Server versions as soon as possible.
• Follow CISA KEV required action: apply vendor mitigations or discontinue use of the affected product if mitigations are unavailable.
• Enforce SmartScreen and Defender Application Control / Attack Surface Reduction rules that block untrusted executables and macros.
• Restrict user ability to run downloaded files from untrusted sources via email and web gateways, and block known malicious file types at the perimeter.
• Monitor for and remove any unpatched or end-of-life Windows builds listed as affected.

Detection

• Hunt for process creation events where executables are launched from user download or temp directories shortly after browser or email client activity.
• Monitor Windows Defender and SmartScreen telemetry for events indicating SmartScreen warnings were suppressed or bypassed.
• Correlate endpoint alerts for file execution with no prior SmartScreen reputation check against known malicious hashes or C2 callbacks.
• Review proxy and DNS logs for downloads of files that later execute on endpoints without corresponding SmartScreen block events.

This assessment is produced automatically and is not human-reviewed. Verify against the vendor advisory before acting on it.