CVE-2026-50315 Overview
CVE-2026-50315 is a null pointer dereference vulnerability in the Windows Image Acquisition (WIA) service. An authenticated local attacker can exploit the flaw to elevate privileges on affected Windows systems. Microsoft published the advisory on July 14, 2026, and the issue is tracked under CWE-476.
The vulnerability affects current Windows 11 client releases and Windows Server 2025 across both x64 and ARM64 architectures. Exploitation requires low-level local privileges and no user interaction, giving attackers a reliable path from a standard user account to SYSTEM.
Critical Impact
Successful exploitation yields full compromise of confidentiality, integrity, and availability on the target host through local privilege escalation.
Affected Products
- Microsoft Windows 11 24H2 (x64, ARM64)
- Microsoft Windows 11 25H2 (x64, ARM64) and Windows 11 26H1 (x64, ARM64)
- Microsoft Windows Server 2025 (x64)
Discovery Timeline
- 2026-07-14 - CVE-2026-50315 published to NVD and Microsoft advisory released
- 2026-07-16 - Last updated in NVD database
Technical Details for CVE-2026-50315
Vulnerability Analysis
The flaw resides in the Windows Image Acquisition subsystem, the platform component that brokers access to scanners and still-image devices for user-mode clients. The service runs with elevated privileges and exposes interfaces reachable by local processes.
An attacker with a low-privilege local account can issue crafted requests that reach a code path where a required pointer is not initialized or validated before use. Dereferencing that pointer under controlled conditions allows the attacker to influence execution in the elevated service context. The result is a local privilege escalation with impact to confidentiality, integrity, and availability on the affected host.
Root Cause
The root cause is a missing null check on a pointer used within the WIA service, classified as [CWE-476] Null Pointer Dereference. Under specific request sequences or object states, the service accesses memory referenced by an unset pointer instead of aborting the operation.
Attack Vector
The attack vector is local and requires an authenticated user session on the target Windows system. No user interaction is required beyond the attacker's own execution. An attacker who already has code execution as a standard user, for example after phishing or through a compromised application, can chain this flaw to obtain SYSTEM privileges and then pursue persistence, credential theft, or lateral movement.
No public proof-of-concept exploit is listed for CVE-2026-50315 at the time of publication, and the vulnerability is not present on the CISA Known Exploited Vulnerabilities catalog. Refer to the Microsoft Security Update CVE-2026-50315 advisory for vendor-provided technical detail.
Detection Methods for CVE-2026-50315
Indicators of Compromise
- Unexpected crashes or restarts of the wiaservc.dll-hosted service or the stisvc (Windows Image Acquisition) service in the System event log.
- New processes spawned as SYSTEM by a parent tied to the WIA service without a corresponding administrative action.
- Standard user accounts performing actions that require elevated privileges shortly after interacting with imaging or scanner APIs.
Detection Strategies
- Hunt for anomalous child processes of svchost.exe instances hosting the Windows Image Acquisition service, especially command interpreters or scripting hosts.
- Correlate service crash events (Event ID 7031, 7034) for stisvc with subsequent privilege changes on the same host.
- Monitor for suspicious loads of WIA-related modules by processes that do not normally interact with imaging devices.
Monitoring Recommendations
- Enable Windows process creation auditing (Event ID 4688) with command-line logging on all Windows 11 and Server 2025 endpoints.
- Baseline the expected callers of WIA interfaces in each environment and alert on deviations from that baseline.
- Track patch compliance for the July 2026 Microsoft security update across affected SKUs and flag hosts that fall out of policy.
How to Mitigate CVE-2026-50315
Immediate Actions Required
- Apply the Microsoft security update referenced in the MSRC advisory for CVE-2026-50315 to all affected Windows 11 24H2, 25H2, 26H1, and Windows Server 2025 systems.
- Prioritize patching on multi-user hosts, jump servers, and virtual desktop infrastructure where local privilege escalation carries the greatest blast radius.
- Review local account membership and remove unnecessary interactive logon rights on servers and shared workstations.
Patch Information
Microsoft addressed CVE-2026-50315 in the July 2026 security update cycle. The authoritative source for build numbers and knowledge base article identifiers is the Microsoft Security Update Guide entry for CVE-2026-50315. Deploy the update through Windows Update, Windows Server Update Services, Microsoft Intune, or your preferred patch management workflow.
Workarounds
- Where imaging devices are not required, disable the Windows Image Acquisition (stisvc) service and set its startup type to Disabled.
- Restrict interactive and remote interactive logon on servers to administrators only, reducing the population of accounts that can trigger the vulnerable code path.
- Apply application control policies such as Windows Defender Application Control to prevent execution of untrusted binaries by standard users pending patch deployment.
# Disable the Windows Image Acquisition service on hosts that do not need it
sc.exe config stisvc start= disabled
sc.exe stop stisvc
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
