CVE-2025-53804: Windows Kernel Driver Info Disclosure—What Admins Must Do

Note: below is a long-form, technically focused feature article about CVE-2025-53804. I drew on Microsoft’s official entry for this CVE and on Microsoft documentation and guidance about kernel-mode drivers and driver blocklists to explain the risk, likely exploitation paths, detection and remediation steps, and recommended defensive actions. Where Microsoft’s advisory gives only limited public detail I call that out and give defensible, practical guidance that applies to this class of vulnerability.
Title: CVE-2025-53804 — Windows Kernel-Mode Driver Information Disclosure: what admins and defenders must know now
Executive summary

• CVE-2025-53804 is an information-disclosure vulnerability in the Windows kernel that Microsoft cataloged in its Security Update Guide as “Windows Kernel-Mode Driver Information Disclosure Vulnerability.” Microsoft’s short description: “Exposure of sensitive information to an unauthorized actor in Windows Kernel allows an authorized attacker to disclose information locally.” (msrc.microsoft.com).
• Public technical details are scarce. Microsoft has recorded the issue in the update guide, but (at the time of writing) Microsoft’s CVE page is the primary official source with limited public technical specifics. Treat this as a confirmed vulnerability in the kernel/driver layer that permits local disclosure of sensitive kernel memory/data when exploited. (msrc.microsoft.com).
• Because the vulnerability is in kernel-mode driver code, exploitation is typically local (the adversary needs local access or to get code running locally) and could be used by an attacker with low or medium privileges to disclose kernel or other protected memory contents; that can yield credentials, secrets, or other sensitive data and may be a stepping stone to privilege escalation or other post-exploit activity. Practical defensive guidance: deploy Microsoft’s security updates as soon as possible; enable and/or enforce the Microsoft Vulnerable Driver Blocklist and HVCI/Memory Integrity where feasible; hunt for suspicious/unsigned or known-vulnerable drivers; and apply endpoint detection rules and memory/driver integrity checks. (msrc.microsoft.com, learn.microsoft.com).

Why this matters (threat model & impact)

• Kernel-mode drivers run with the highest privileges on Windows. A vulnerable driver that mismanages buffers, I/O request states, or object access can inadvertently return kernel memory to user-mode callers or otherwise expose data. Information-disclosure vulnerabilities in kernel drivers can leak sensitive structures (token data, cryptographic keys, cached credentials, handles) that attackers use for lateral movement or privilege escalation. The Windows driver security model makes such bugs particularly consequential because kernel-mode code has direct access to kernel memory and OS internals. (learn.microsoft.com).
• The Microsoft entry for CVE-2025-53804 explicitly categorizes it as an information disclosure in the kernel — i.e., sensitive information can be exposed to an unauthorized actor via local interaction. That makes affected hosts a risk to confidentiality of secrets stored in or reachable from kernel memory, and it increases the value of a local foothold to an attacker. (msrc.microsoft.com).
• Typical exploitation scenarios: an authenticated local user or malicious process triggers a vulnerable driver IOCTL or other functionality that returns more data than intended or copies kernel memory into user buffers. That returned data can contain secrets or internal state. In some situations disclosure can enable privilege escalation or bypass mitigations by exposing kernel pointers or symbol information. (This is how many historical kernel info-leak vulnerabilities have been used.) (learn.microsoft.com).

What Microsoft says (and what it doesn’t)

• Microsoft’s official CVE page: it lists the vulnerability and a short description emphasizing local information disclosure. The CVE entry (Microsoft Security Update Guide) is the authoritative record for affected components, the severity rating, and patch availability. Systems administrators should treat the Microsoft advisory as the primary source for the exact products and KBs affected and for Microsoft’s published remediation guidance. (msrc.microsoft.com).
• Publicly available, detailed technical write-ups or proof-of-concept exploit code for CVE-2025-53804 do not appear widely published at this time; that reduces the immediate risk of mass exploitation but does not remove urgency: information disclosure in kernel drivers remains a high-priority remediation item because it can be used in chained attacks. (If you need public exploit or research write-ups, watch reputable sources and Microsoft’s CVE page for any updates or technical analysis releases.) (msrc.microsoft.com).

Technical background — how kernel driver information leaks typically happen

• Common root causes:
• Incorrectly setting IO status bytes/lengths (driver reports more data returned than filled, and leftover kernel memory is copied to user buffers).
• Failure to zero/initialize buffers before returning them to user-mode.
• Use of kernel handles or ZwCreateFile without forcing access checks (OBJ_FORCE_ACCESS_CHECK) in filter drivers, exposing data bypassing normal ACLs.
• Reading or returning internal kernel objects directly to user-mode without sanitization. (learn.microsoft.com).
• Typical attack flow:
• Adversary with local execution capability calls a vulnerable driver entry point (IOCTL or read/write) with crafted parameters.
• Driver returns a response containing kernel memory or other unintended contents.
• Attacker extracts secrets (tokens, pointers, keys) or structural information (addresses, kernel layout) used to defeat KASLR or to craft privilege-escalation exploits.
• Use of leaked information to escalate privileges, move laterally, or persist. (learn.microsoft.com).
• Because the root causes are coding mistakes in kernel-mode driver logic, remediation usually requires a vendor-supplied patch. Microsoft’s guidance and patched KBs are therefore the primary fix path. (msrc.microsoft.com).

Known scope & severity (what to check in Microsoft’s advisory)

• Always inspect the Microsoft Security Update Guide page for the CVE to confirm:
• Which Windows versions and KB numbers are affected.
• Microsoft’s severity rating and the CVSS (if provided).
• Any workarounds, mitigation advice, or KB-linked patches.
• Known issues or compatibility notes tied to the update.
  Microsoft’s CVE page is the authoritative source. (msrc.microsoft.com).
• If Microsoft has issued a patch or included the fix in a Patch Tuesday rollup, deploy that update quickly in a test ring and then to production. In many recent months Microsoft has issued kernel patches in monthly security updates — check the monthly release notes and security update guide for the relevant KB IDs and release dates. (msrc.microsoft.com).

Immediate triage checklist (24–72 hours)

• Confirm Microsoft’s KBs and patch status:
• Look up CVE-2025-53804 in the Microsoft Security Update Guide and note the KB/patch IDs and release date. Apply the Microsoft update per normal change-control/testing processes. (MSRC is the authoritative source for this CVE.) (msrc.microsoft.com).
• If patching cannot be immediate, enable mitigations:
• Ensure the Microsoft Vulnerable Driver Blocklist and Memory Integrity (HVCI) are enabled where feasible — these features prevent loading known vulnerable drivers and strengthen kernel integrity. Microsoft documents how the vulnerable driver blocklist is enforced and advises enabling HVCI/Memory Integrity or applying the blocklist via App Control for Business. (learn.microsoft.com).
• Apply attack-surface reduction (ASR) rules where relevant — in particular, Microsoft recommends rules that block abuse of exploited signed drivers. (learn.microsoft.com).
• Hunt for suspicious drivers and recent driver installs:
• Inventory loaded drivers (see “practical detection” below).
• Identify any third-party or unsigned driver files recently installed or that match known-vulnerable vendor names.
• Limit local/guest write access:
• Restrict the ability of non-privileged users/processes to install drivers or write to driver directories.
• Monitor detection telemetry:
• Increase logging and watch for anomalous IOCTL/driver interaction and suspicious accesses to driver device objects.

Enabling & using Microsoft’s Vulnerable Driver Blocklist (practical)

• What it does: Microsoft’s vulnerable driver blocklist is intended to prevent known vulnerable or malicious (signed) drivers from loading; it is enforced by HVCI/Memory Integrity and can be distributed via Windows Update or applied by App Control policies for business environments. For many systems, turning on Memory Integrity enforces this blocklist. (learn.microsoft.com).
• How to check and enable (quick):
• GUI: Settings → Privacy & security → Windows Security → Device security → Core isolation → Core isolation details → toggle Memory Integrity.
• PowerShell: to check/set the blocklist preference for Defender you can use Get-MpPreference / Set-MpPreference (for example Set-MpPreference -EnableVulnerableDriverBlocklist $true). Use group policy or App Control for Business for enterprise-wide enforcement. (Note: enabling HVCI/Memory Integrity may require a reboot and may expose compatibility issues with some legacy drivers — test before broad rollout.) (ninjaone.com, learn.microsoft.com).
• Caveat: historically there have been platform/servicing nuances in how frequently the blocklist is updated for some OS versions; verify that your environment is receiving blocklist updates and consider pushing the most up-to-date blocklist through App Control if you rely heavily on this control. Reporting and update cadence details are on Microsoft’s guidance pages. (csoonline.com, learn.microsoft.com).

Practical detection and hunting (procedures & sample commands)
Note: these are defensive checks you can run as admin. Adapt to your environment and test before mass-deployment.
1) Inventory loaded drivers (quick Windows commands)

• PowerShell (list drivers and signing status):
• Get-WmiObject Win32_SystemDriver | Select Name, PathName, State, StartMode
• Use sigcheck (Sysinternals) to verify driver signatures: sigcheck -m c:\windows\system32\drivers*.sys
• driverquery (built-in):
• driverquery /v /fo list
• These show what drivers are present and whether they are signed, dates, and file paths.

2) Look for recent driver installs or unsigned drivers

• Use file timestamp queries or package management logs (e.g., Windows Update, vendor installers).
• Search for drivers in typical driver folders (C:\Windows\System32\drivers) with suspicious timestamps.

3) Monitor for unusual IOCTL usage (hunt for driver device-object interactions)

• Instrument endpoints for process-to-driver IOCTL calls where possible via EDR telemetry or kernel tracing.
• Look for unusual processes that open handles to device names like .\SomeDevice and then perform unusual reads/writes.

4) Hunting rules / detection signature examples (conceptual)

• Alert on a non-admin process opening a handle to a kernel device and issuing frequent IOCTLs.
• Alert on loading of a known-vulnerable driver filename or driver signed by an unexpected vendor.
• Alert on drivers newly written to disk in driver directories followed by immediate load.

5) Memory-level artifacts

• If you suspect exploitation, collect a memory image for forensic analysis: kernel memory dumps can reveal late-loaded drivers and content leaked into user buffers. Use forensics tools per your incident response playbook.

Mitigation & remediation — recommended steps

• Patch promptly: apply the Microsoft updates/KBs addressing CVE-2025-53804 as listed on Microsoft’s Security Update Guide page. That is the primary remediation. (msrc.microsoft.com).
• Enforce driver blocklists and HVCI/Memory Integrity: enable Microsoft’s Vulnerable Driver Blocklist and HVCI where feasible and tested; use App Control for Business to apply the latest blocklist enterprise-wide. (learn.microsoft.com, ninjaone.com).
• Restrict driver installation: limit who/what can install kernel drivers (Group Policy / device guard / administrative controls), and monitor for unexpected driver installs.
• Vendor/driver updates: identify third-party drivers in your environment and ensure vendors have released patched versions; replace or remove legacy drivers that are no longer supported.
• Detection & EDR: tune EDR/NGAV to flag unusual driver loads, device-object access patterns, and unexpected IOCTL invocation by user-mode processes.

For incident responders: containment & evidence

• If you confirm exploitation or suspect local info-leak activity on a host:
• Isolate the host from critical networks (to prevent lateral movement).
• Capture volatile data and a memory image (prioritize kernel memory capture).
• Collect driver lists, Windows event logs (System, Security), and EDR telemetry showing process/driver interactions.
• Preserve copies of suspicious driver files for static analysis and vendor contact.
• Apply patches and/or block the specific vulnerable driver from loading, then validate system integrity. (Roll back only if a patch causes unacceptable disruption and you have a tested rollback plan.)
• Keep Microsoft’s advisory and KBs handy during triage; they may include vendor-specific mitigations or blocking workarounds. (msrc.microsoft.com).

Risk prioritization for IT teams

• Prioritize endpoints that:
• Store or handle sensitive secrets or credentials (domain controllers, certificate servers, privileged admin systems).
• Run third-party drivers from vendors who historically have had driver issues, or run legacy drivers that cannot be easily updated.
• Are accessible by many users (shared workstations, jump hosts) or host critical services.
• For general estate: treat kernel-mode information-disclosure CVEs as moderately high to high priority for patching, because they can materially increase the risk of credential theft and privilege escalation.

Timeline & disclosure notes

• Microsoft’s Security Update Guide is the authoritative source for disclosure timeline, patch release dates, and affected KB numbers. Always refer to the CVE page there for the latest timeline and any “exploit observed in the wild” statements. (msrc.microsoft.com).
• At the time of writing, public analysis for CVE-2025-53804 is limited; defenders should not rely on the lack of public exploit code as a reason to delay patching.

Why driver security controls matter (broader context)

• Microsoft’s Vulnerable Driver Blocklist and HVCI are controls specifically intended to block the class of “bring your own vulnerable driver” and known vulnerable driver attacks that bypass user-mode protections. Blocking or preventing known vulnerable drivers from loading closes one of the most common attack vectors for kernel-level abuse. Enterprises should plan to adopt and enforce these controls as part of a layered defense. (learn.microsoft.com).
• Note there have been historical servicing and update-cadence nuances with the vulnerable driver blocklist for some OS versions; validate blocklist update behavior in your environment and consider pushing the latest blocklist via App Control or other management tools if you rely on it heavily. (csoonline.com).

Sample quick playbook (for small-medium IT teams)

• Immediately: read Microsoft’s CVE page and note KB IDs. Plan update deployment. (msrc.microsoft.com).
• 0–24 hours: enable Vulnerable Driver Blocklist / Memory Integrity on test devices; verify driver compatibility.
• 24–72 hours: push patches to test ring; run driver inventory to find third-party drivers that might be vulnerable.
• 72 hours–2 weeks: deploy patches widely; enforce driver blocklist via App Control or GPO where appropriate; update EDR detection rules to flag driver IOCTL anomalies.
• 2–4 weeks: review logs, memory captures (if any suspicious events), and vendor updates for drivers in your environment.

Concluding recommendations (actionable)

• Do not wait for public exploits. Apply Microsoft’s fixes for CVE-2025-53804 as published in the Security Update Guide and test the updates in your environment quickly. (msrc.microsoft.com).
• Use the Vulnerable Driver Blocklist + HVCI/Memory Integrity and App Control for Business as practical controls to prevent known vulnerable drivers from loading. Validate blocklist update behavior and push the latest list where necessary. (learn.microsoft.com, csoonline.com).
• Hunt proactively: inventory drivers, identify unsigned or out-of-date third-party drivers, and monitor for suspicious driver activity (unexpected device handle usage, repeated IOCTLs from user-mode processes).
• Prepare an IR plan that includes memory capture and driver artifact preservation in case exploitation is suspected.

References and key links

• Microsoft Security Update Guide — CVE-2025-53804 (official CVE entry). (msrc.microsoft.com).
• Microsoft Learn — Microsoft recommended driver block rules / Vulnerable Driver Blocklist guidance. (learn.microsoft.com).
• Microsoft Learn — Kernel-mode driver architecture and design guidance (background on kernel drivers). (learn.microsoft.com).
• Microsoft Learn — Information Disclosure (common causes and examples for driver information leaks). (learn.microsoft.com).
• MSRC blog, March 2025 Patch Tuesday overview (context for Windows kernel fixes and patch cadence). (msrc.microsoft.com).
• CSO Online — practical discussion of driver blocklist servicing and update cadence (operational note: validate blocklist updates in your environment). (csoonline.com).

If you want next steps from me

• I can:
• Lookup the exact KB number(s) and Microsoft patch release date(s) associated with CVE-2025-53804 and produce a short script or SCCM/Intune targeting plan for your environment (I’ll fetch the KB details from Microsoft’s guide and cite them).
• Produce a short checklist or runbook (one-page) you can hand to ops with the exact PowerShell commands and SCCM/WSUS/Intune deployment steps for rolling the patch to test and production rings.
• Create a set of EDR/SIEM detection queries (e.g., Splunk/Sysmon/Elastic) tuned to hunting driver IOCTL abuse and for detecting newly loaded drivers matching risky attributes.

Which of those would be most useful right now?

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Source: MSRC Security Update Guide - Microsoft Security Response Center