CVE-2026-50470 Overview
CVE-2026-50470 is an out-of-bounds read vulnerability in the Windows Network Policy Server (NPS) SNMP component. The flaw allows an unauthenticated remote attacker to disclose sensitive information by sending crafted network requests to an affected system. The vulnerability is classified under [CWE-125] (Out-of-bounds Read) and requires no user interaction or prior privileges. Microsoft published guidance for this issue through the Microsoft Security Response Center on July 14, 2026.
Critical Impact
An unauthenticated attacker can read memory contents beyond intended buffer boundaries over the network, potentially exposing sensitive process memory from the Network Policy Server service.
Affected Products
- Windows Network Policy Server (SNMP component)
- Refer to the Microsoft Security Update CVE-2026-50470 advisory for the complete list of affected Windows Server versions and build numbers.
Discovery Timeline
- 2026-07-14 - CVE-2026-50470 published to NVD
- 2026-07-15 - Last updated in NVD database
Technical Details for CVE-2026-50470
Vulnerability Analysis
The vulnerability resides in how the Windows Network Policy Server processes Simple Network Management Protocol (SNMP) messages. NPS is the Microsoft implementation of a RADIUS server and proxy used for centralized authentication, authorization, and accounting of network access requests. The SNMP handling code within NPS reads memory beyond the bounds of an allocated buffer when parsing attacker-supplied input.
An attacker who successfully exploits this flaw can retrieve fragments of process memory. Disclosed content may include authentication material, RADIUS shared secrets, session tokens, or other data resident in the NPS service address space. The attack requires only network reachability to the SNMP interface of the target system.
Root Cause
The root cause is an out-of-bounds read [CWE-125] triggered during SNMP message parsing. The code fails to validate a length or offset field before dereferencing a buffer pointer. When the parser encounters a malformed value, it reads adjacent memory and returns that content within its response or error path.
Attack Vector
The attack vector is network-based and does not require authentication or user interaction. An attacker sends a crafted SNMP request to a Windows host running the Network Policy Server role with the vulnerable SNMP component reachable. The malformed request triggers the out-of-bounds read, and the server returns memory contents in the response.
No public proof-of-concept exploit code is available at the time of publication. Refer to the Microsoft Security Update CVE-2026-50470 advisory for the vendor's technical description.
Detection Methods for CVE-2026-50470
Indicators of Compromise
- Unexpected inbound SNMP traffic on UDP port 161 directed at Windows servers running the Network Policy Server role.
- Malformed or oversized SNMP GET, GETNEXT, or GETBULK protocol data units in packet captures.
- Anomalous outbound response sizes from the NPS host to external SNMP clients.
Detection Strategies
- Deploy network intrusion detection signatures that inspect SNMP packet structure for length-field inconsistencies and truncated variable bindings.
- Enable SNMP protocol logging and monitor Windows Event Logs for the Network Policy Server service (IAS event source) for unusual activity patterns.
- Correlate SNMP query sources against an allowlist of authorized network management stations.
Monitoring Recommendations
- Alert on SNMP requests originating from IP addresses outside the approved management network.
- Track response-size distributions from NPS hosts and flag statistical outliers that may indicate memory disclosure.
- Monitor for repeated malformed SNMP queries from a single source, which may indicate exploitation attempts or reconnaissance.
How to Mitigate CVE-2026-50470
Immediate Actions Required
- Apply the Microsoft security update referenced in the Microsoft Security Update CVE-2026-50470 advisory as soon as tested in your environment.
- Inventory all Windows systems with the Network Policy Server role and the SNMP feature installed, and prioritize patching for internet-adjacent hosts.
- Restrict SNMP access on affected servers to trusted management subnets using host and network firewall rules.
Patch Information
Microsoft has issued a security update for CVE-2026-50470. Consult the Microsoft Security Update CVE-2026-50470 page for the exact KB article, supported product versions, and installation guidance.
Workarounds
- Disable the SNMP feature on Windows hosts where it is not required for operations.
- Block UDP port 161 at perimeter and internal segmentation firewalls except for approved management stations.
- Place Network Policy Server hosts on isolated management VLANs with strict ingress filtering.
# Example: Restrict SNMP inbound traffic to a specific management host using Windows Firewall
New-NetFirewallRule -DisplayName "Restrict SNMP to Management Station" `
-Direction Inbound `
-Protocol UDP `
-LocalPort 161 `
-RemoteAddress 10.10.10.5 `
-Action Allow
New-NetFirewallRule -DisplayName "Block All Other SNMP" `
-Direction Inbound `
-Protocol UDP `
-LocalPort 161 `
-Action Block
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
