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NULL Pointer DereferenceWeakness · CWE-476

CVE-2025-11156

MEDIUM · 5.9 CVSS v4.0 Published 2025-11-28
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
61/100
Remediation priority · Elevated
Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Netskope was notified about a potential gap in its agent (NS Client) on Windows systems. If this gap is successfully exploited, a local, authenticated user with Administrator privileges can improperly load the driver as a generic kernel service. This triggers the flaw, causing a system crash (Blue-Screen-of-Death) and resulting in a Denial of Service (DoS) for the affected machine.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · moderate confidence

The Netskope NS Client for Windows contains a vulnerability where a local authenticated user with Administrator privileges can improperly load the driver as a generic kernel service instead of its intended protected context, triggering a flaw that causes a Blue Screen of Death and resulting in Denial of Service.

MitigationApply vendor-provided patches/updated agent versions when available. Until then, restrict Administrator access to only necessary personnel and monitor for suspicious driver loading activities using Windows Event Log or EDR tools.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
High
Authentication
X
User interaction
None
Scope
X

CVSS:4.0/AV:L/AC:L/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Identify if Netskope NS Client is installed
    Open Programs and Features (appwiz.cpl) or check C:\Program Files\Netskope for the NS Client installation directory
    Affected if Netskope NS Client for Windows is present on the system
  2. Determine installed Netskope NS Client version
    Check the installed version via Windows Registry at HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\Netskope NS Client\DisplayVersion, or right-click the executable in the installation folder and view Properties > Details
    Affected if Installed version falls within the vulnerable version range for this CVE (compare against vendor-advisory version numbers)
  3. Verify presence of Administrator accounts
    Open Computer Management > Local Users and Groups > Groups > Administrators, or run 'net localgroup administrators' from command prompt
    Affected if Any non-standard Administrator accounts exist beyond the intended protected admin context
  4. Check Windows Event Logs for driver loading anomalies
    Open Event Viewer > Windows Logs > System and search for Event ID 219 (Microsoft-Windows-Kernel-PnP/Driver Monitoring) or Event ID 219 (Driver Manager), filtering for Netskope driver entries (NS*)
    Affected if Netskope driver (ns*) is being loaded outside its intended protected service context or generating kernel-mode fault events
  5. Monitor for Blue Screen events correlated with Netskope driver
    Check Windows Event Viewer > Windows Logs > System for BugCheck events (Event ID 1001) with BugcheckCode referencing kernel-mode faults, and cross-reference with Netskope driver activity
    Affected if BSOD events occur with Netskope driver loaded and active, indicating the DoS condition is triggered

A user is affected if Netskope NS Client for Windows is installed, the installed version is within the vulnerable range, and an Administrator-privileged user can trigger improper driver loading causing a Blue Screen of Death.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Apply vendor-provided patches/updated agent versions when available. Until then, restrict Administrator access to only necessary personnel and monitor for suspicious driver loading activities using Windows Event Log or EDR tools.

Have this fixed Scoped from the published advisory
  • Consultation3.0 h
  • Implementation2.0 h
  • Testing3.0 h
  • Review / QA2.0 h
10.0 hours of engineering $1,770
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-11156 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data