CVE-2025-59502 – This vulnerability in Windows Remote Procedure ... (How to Fix)

Q: What is the severity of CVE-2025-59502?

CVE-2025-59502 has a CVSS score of 7.5 (HIGH). This vulnerability in Windows Remote Procedure Call allows unauthorized attackers to cause denial of service by consuming excessive system resources. It affects Windows systems with RPC enabled, potentially disrupting legitimate services and operations.

📋 TL;DR

This vulnerability in Windows Remote Procedure Call allows unauthorized attackers to cause denial of service by consuming excessive system resources. It affects Windows systems with RPC enabled, potentially disrupting legitimate services and operations.

💻 Affected Systems

Products:

Windows Remote Procedure Call

Versions: Specific Windows versions as listed in Microsoft advisory

Operating Systems: Windows

Default Config Vulnerable: ⚠️ Yes

Notes: Systems with RPC enabled and exposed to network are vulnerable. Default Windows configurations typically have RPC services running.

📦 What is this software?

⚠️ Risk & Real-World Impact

🔴

Worst Case

Complete system unavailability or crash affecting all RPC-dependent services, potentially requiring system reboot and causing extended downtime.

🟠

Likely Case

Degraded system performance, service interruptions, and resource exhaustion affecting specific applications using RPC.

🟢

If Mitigated

Minimal impact with proper network segmentation, rate limiting, and monitoring in place.

🌐 Internet-Facing: HIGH

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: LOW

Attack requires network access to RPC endpoint but no authentication. Simple resource exhaustion attacks are relatively easy to execute.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: Check Microsoft Security Update Guide for specific KB numbers

Vendor Advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-59502

Restart Required: Yes

Instructions:

1. Apply latest Windows security updates from Microsoft. 2. Restart affected systems. 3. Verify patch installation via Windows Update history.

🔧 Temporary Workarounds

Network Segmentation

windows

Restrict RPC access to trusted networks only

Use Windows Firewall: netsh advfirewall firewall add rule name="Block RPC" dir=in action=block protocol=TCP localport=135,445,593
Use Group Policy to restrict RPC access

Rate Limiting

all

Implement network-level rate limiting for RPC traffic

🧯 If You Can't Patch

Implement strict network access controls to limit RPC exposure
Deploy intrusion prevention systems with DoS protection capabilities

🔍 How to Verify

Check if Vulnerable:

Check Windows version and installed updates against Microsoft advisory

Check Version:

systeminfo | findstr /B /C:"OS Name" /C:"OS Version"

Verify Fix Applied:

Verify KB update is installed via: wmic qfe list | findstr KB[number]

📡 Detection & Monitoring

Log Indicators:

Excessive RPC connection attempts
System resource exhaustion alerts
RPC service failures in Event Viewer

Network Indicators:

High volume of RPC traffic from single sources
Abnormal RPC request patterns

SIEM Query:

source="windows" AND (event_id=4625 OR event_id=4688) AND process_name="svchost.exe" AND process_command_line LIKE "%rpc%"

📊 Metadata

CVE ID: CVE-2025-59502

CVSS v3 Score: 7.5 (HIGH)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE: CWE-400

EPSS Score: 14.06% exploit probability (94.2th percentile)

Published: October 14, 2025

Last Updated: October 22, 2025

🔗 References

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2025-59502 Vendor Advisory

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