CVE-2025-64656
📋 TL;DR
This vulnerability allows an unauthorized attacker to perform an out-of-bounds read in Application Gateway, potentially leading to privilege escalation over a network. Organizations using Microsoft Application Gateway are affected, particularly those with internet-facing deployments.
💻 Affected Systems
- Microsoft Application Gateway
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with administrative privileges, data exfiltration, and lateral movement across the network.
Likely Case
Information disclosure leading to credential theft or configuration data exposure, enabling further attacks.
If Mitigated
Limited impact due to network segmentation and proper access controls, potentially only affecting isolated components.
🎯 Exploit Status
Exploitation requires network access but no authentication, though specific conditions may be needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Microsoft Security Update Guide for specific version
Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-64656
Restart Required: Yes
Instructions:
1. Review Microsoft Security Advisory. 2. Apply the latest security update for Application Gateway. 3. Restart the Application Gateway service. 4. Verify the patch is applied correctly.
🔧 Temporary Workarounds
Network Segmentation
allRestrict network access to Application Gateway to trusted sources only.
Use firewall rules to limit inbound traffic to specific IP ranges.
Disable Unnecessary Features
allTurn off any non-essential Application Gateway features to reduce attack surface.
Review and disable unused modules or configurations in Application Gateway settings.
🧯 If You Can't Patch
- Implement strict network access controls and monitor for suspicious activity.
- Isolate the Application Gateway in a segmented network zone with limited trust.
🔍 How to Verify
Check if Vulnerable:
Check the Application Gateway version against the patched version listed in the Microsoft advisory.Check Version:
Get-ApplicationGatewayVersion (PowerShell) or equivalent command for your deployment.Verify Fix Applied:
Confirm the Application Gateway version matches or exceeds the patched version after update.📡 Detection & Monitoring
Log Indicators:
- Unusual out-of-bounds read errors in Application Gateway logs
- Failed authentication attempts from unexpected sources
Network Indicators:
- Anomalous network traffic patterns to Application Gateway ports
- Unexpected data exfiltration attempts
SIEM Query:
source="ApplicationGateway" AND (error="out-of-bounds" OR event="privilege escalation")