CVE-2025-29830 Overview
CVE-2025-29830 is an information disclosure vulnerability in Windows Routing and Remote Access Service (RRAS). The flaw stems from the use of an uninitialized resource [CWE-908], allowing an unauthorized remote attacker to read memory contents that should not be exposed over the network. Successful exploitation requires user interaction, such as convincing a user to connect to a malicious server or open a crafted file. Microsoft published the advisory on May 13, 2025, affecting a broad range of Windows client and server editions. The vulnerability impacts confidentiality only, with no direct effect on integrity or availability.
Critical Impact
An unauthorized attacker can disclose memory contents from a vulnerable RRAS host over the network, potentially leaking sensitive data such as credentials, pointers, or configuration fragments useful for follow-on attacks.
Affected Products
- Microsoft Windows 10 (versions 1507, 1607, 1809, 21H2, 22H2)
- Microsoft Windows 11 (versions 22H2, 23H2, 24H2)
- Microsoft Windows Server 2008, 2012, 2016, 2019, 2022, 2022 23H2, and 2025
Discovery Timeline
- 2025-05-13 - CVE-2025-29830 published to NVD
- 2025-05-13 - Microsoft releases security update for CVE-2025-29830
- 2025-05-19 - Last updated in NVD database
Technical Details for CVE-2025-29830
Vulnerability Analysis
The Routing and Remote Access Service (RRAS) provides routing, VPN, and dial-up remote access functionality on Windows. CVE-2025-29830 is classified as a use of uninitialized resource weakness [CWE-908]. RRAS allocates a buffer or structure and transmits it over the network before all fields are initialized with intended values. The residual memory may contain data left by previous operations, including pointers, stack fragments, or sensitive process state.
An attacker who can induce a user to interact with an attacker-controlled RRAS endpoint receives responses containing uninitialized memory. Repeated requests can be used to map process layout or extract sensitive content. The flaw is network-reachable and does not require authentication, but it does require user interaction, which constrains mass exploitation.
Root Cause
The root cause is failure to zero or fully populate a memory region before it is serialized into a network response within RRAS. This is a common class of bug in protocol handling code where structure padding, optional fields, or error-path responses are returned without sanitization.
Attack Vector
Exploitation occurs over the network and depends on user interaction. A typical scenario involves an attacker hosting a malicious server or sending a crafted message that prompts the RRAS component on the target system to respond with data containing uninitialized memory. The disclosed bytes are not attacker-controlled but can include sensitive process memory. No public proof-of-concept code or in-the-wild exploitation has been reported, and the issue is not listed on the CISA Known Exploited Vulnerabilities catalog.
No verified public exploit code is available. Refer to the Microsoft Security Update for CVE-2025-29830 for vendor technical details.
Detection Methods for CVE-2025-29830
Indicators of Compromise
- Unexpected outbound RRAS or VPN session establishment from client systems to untrusted external endpoints.
- Anomalous inbound traffic to TCP/UDP ports associated with RRAS (PPTP 1723, L2TP 1701, IKE 500/4500) on hosts where RRAS should not be exposed.
- Repeated short-lived RRAS sessions from a single remote source consistent with memory-disclosure scraping behavior.
Detection Strategies
- Monitor for the RemoteAccess service running on systems that do not have a documented RRAS role.
- Inspect network telemetry for RRAS protocol responses being sent to external or untrusted networks.
- Correlate user-initiated connections to unfamiliar VPN or remote access servers with subsequent suspicious memory patterns or credential reuse alerts.
Monitoring Recommendations
- Enable Windows Event Log collection for the RRAS service (Microsoft-Windows-RasServer and related channels) and forward to a centralized SIEM.
- Track patch deployment status for the May 2025 Microsoft security updates across all Windows endpoints and servers.
- Alert on first-time RRAS connections initiated by end-user devices to non-corporate destinations.
How to Mitigate CVE-2025-29830
Immediate Actions Required
- Apply the May 2025 Microsoft security updates referenced in the Microsoft Security Update Guide to all affected Windows client and server versions.
- Inventory systems running the RemoteAccess service and disable it where RRAS is not a required role.
- Restrict inbound and outbound RRAS-related traffic at the network perimeter to known, trusted endpoints only.
Patch Information
Microsoft released patches addressing CVE-2025-29830 on May 13, 2025, distributed through standard Windows Update channels and the Microsoft Update Catalog. Coverage includes Windows 10 (1507 through 22H2), Windows 11 (22H2, 23H2, 24H2), and Windows Server 2008 through 2025. Administrators should validate patch installation using Get-HotFix or update compliance tooling.
Workarounds
- Disable the Routing and Remote Access service on hosts where it is not required: sc.exe config RemoteAccess start= disabled followed by sc.exe stop RemoteAccess.
- Block RRAS protocol ports (PPTP 1723, L2TP 1701, IKE 500/4500, GRE) at firewalls for hosts that do not need to provide remote access.
- Train users to avoid connecting to unverified VPN or remote access endpoints, since exploitation requires user interaction.
# Configuration example: disable RRAS on systems that do not require it
sc.exe stop RemoteAccess
sc.exe config RemoteAccess start= disabled
# Verify patch installation status (PowerShell)
Get-HotFix | Sort-Object -Property InstalledOn -Descending | Select-Object -First 20
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
