CVE-2025-55676 Local Info Leak in Windows USB Video Class Driver (UVC)

The Microsoft Security Update Guide has recorded CVE-2025-55676 as an information‑disclosure flaw in the Windows USB Video Class (UVC) System Driver that can cause an error message to reveal sensitive kernel or system data to a local, authorized actor—making it a local information‑leak vulnerability that administrators should treat as a high‑priority remediation item.

Background / Overview​

USB Video Class (UVC) drivers (usbvideo.sys and related stack components) are the Windows kernel driver set that implements the standard USB Video Class protocol used by webcams, document cameras, capture devices, and many consumer USB video peripherals. Because UVC drivers run in kernel mode and interact directly with device descriptors and negotiated buffers from hardware, mistakes in handling device responses, error paths, or status messages can expose kernel memory or privileged data to user‑mode processes or attached devices. Historically, the UVC driver family has produced multiple security advisories and patches across recent years, making the component a recurring target for security research and exploitation.
CVE‑2025‑55676 is described by Microsoft as “generation of error message containing sensitive information in Windows USB Video Driver” and the public trackers list a CVSS v3.1 base score of 5.5 (Medium), with an attack vector classified as local (not remotely exploitable) and confidentiality impact rated high for the specific paths the vendor annotated.
This advisory is notable for three operational reasons:

• The vulnerability is in a kernel‑mode driver, so any data leak can materially aid an attacker in post‑compromise escalation or in constructing further kernel exploits.
• Microsoft’s public advisory entries are deliberately terse for many kernel info‑leak issues; the Update Guide entry is the canonical record for affected SKUs and KB mappings. Administrators must use MSRC as their primary source when mapping CVE→KB→build.
• The exploitation vector is local (requires code or device interaction on the host), but local does not mean low‑risk: shared systems, kiosks, RDP/VDI hosts, and any environment that permits untrusted local code or devices are especially exposed.

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What is known (technical summary)​

The bug class and immediate impact​

• The public descriptions classify CVE‑2025‑55676 as a CWE‑209: Generation of error message containing sensitive information. In practice this means an error handling path or logging/error response routine is returning or embedding data that should be treated as secret (kernel pointers, partial kernel memory, authentication artifacts, or other internal state).
• The vulnerability enables a local, authorized actor to obtain confidential information from the host; Microsoft’s advisory and public trackers emphasize local information disclosure rather than remote code execution.

Likely exploitation pattern (based on public class and prior UVC issues)​

Historical, analogous UVC and usbvideo.sys vulnerabilities reveal common root causes that are likely relevant here:

• A driver returns more bytes in an error/response than it actually populated (leftover kernel memory leaked into user buffers).
• A failure to sanitize or zero buffers that are later reflected into error messages or diagnostic responses.
• Device descriptor parsing or control‑transfer paths that leak kernel memory through crafted device responses when probed by an attached USB device.

Given those patterns, a realistic exploitation scenario is:

• A process with local access, or a malicious USB device plugged into a live machine, triggers a routine in the UVC stack that produces an error or diagnostic response.
• That response is constructed incorrectly and includes kernel or privileged memory contents.
• The attacker reads that output and extracts secrets, kernel layout information (which aids in bypassing KASLR), tokens, or other artifacts that lower the bar for privilege escalation.

Attack prerequisites and scope​

• Exploitation requires the ability to interact with the victim host locally: either code execution as a local user, a local process that can talk to the driver, or direct physical access to the machine to attach a malicious USB video device. Public trackers mark the vector as local, not network‑remote.
• A successful leak can materially increase the value of a local foothold by revealing secrets or kernel addresses and thereby enabling chained attacks (privilege escalation or control‑flow bypass).

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What Microsoft (and public trackers) say — verification and confidence​

Microsoft’s Security Update Guide lists CVE‑2025‑55676 in the Update Guide entry for the vulnerability; outside trackers (CVE aggregators and vulnerability feeds) have mirrored that advisory and report a CVSS v3.1 score of 5.5 with the CWE classification CWE‑209. These independent mirrors include vulnerability aggregators that pulled the MSRC record directly. The public citation entries and the MSRC mapping are the authoritative place to confirm which Windows builds and KB articles include the patch.
Caveat and verification note: MSRC’s Update Guide is a dynamic, client‑side web app; some automated scrapers do not render the full advisory unless JavaScript is enabled. Because of that, third‑party mirrors sometimes index the headline but not full KB mappings; administrators must confirm the exact KB IDs for their builds in an interactive browser or via the Microsoft Update Catalog before automating remediation.

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Cross‑reference: corroboration from independent sources​

To build operational confidence in the advisory, the following independent feeds corroborate the MSRC entry:

• Aggregated CVE databases that mirror vendor advisories and list CVSS/CWE details for CVE‑2025‑55676.
• Security‑feed aggregators and public CVE trackers that summarize the vulnerability, the vector (local), and the recommended mitigation (apply Microsoft’s patch).

These independent sources match Microsoft’s high‑level description (local information disclosure via error message generation), the CWE mapping, and the medium CVSS rating. Where independent feeds diverge or omit KB mappings, rely on MSRC as the canonical authority and the Microsoft Update Catalog for exact package names.

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Why this matters — threat model and operational risk​

Information‑disclosure bugs in kernel drivers are disproportionately valuable to attackers because they:

• Reveal kernel layout or pointer information useful in bypassing Kernel Address Space Layout Randomization (KASLR).
• Leak authentication artifacts, cryptographic keys, or cached secrets that can be used for lateral movement or account takeover.
• Serve as a stepping stone to privilege escalation: attackers use leaks to craft reliable, targeted exploitation chains.

Environments of particular concern:

• Multi‑user machines: RDP/VDI hosts, lab workstations, kiosk devices, or classroom desktops where untrusted users run code.
• Shared or public computers where an attacker can physically plug a malicious USB device.
• Any host that stores or has access to high‑value secrets (credential stores, certificate keys, token caches).

Even single‑user, well‑hardened systems should be patched: while the immediate exploitation complexity is higher than a remote RCE, the long‑term risk of chained attacks makes prompt remediation the right operational choice.

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Patch status, mapping, and practical triage​

Public trackers indicate a Microsoft patch is available for CVE‑2025‑55676; aggregated feeds flag a published advisory and recommend installing the vendor update. Use this prioritized triage checklist:

• Confirm the MSRC Update Guide entry for CVE‑2025‑55676 and record the exact KB article(s) and build SKUs the advisory lists. The MSRC entry is authoritative; third‑party mirrors are useful for context but may lag in mapping.
• Pull the exact update packages from the Microsoft Update Catalog or through your established patch management (WSUS, SCCM/ConfigMgr, Intune/Windows Update for Business) so you can test and deploy using your normal change‑control processes.
• Test in a representative pilot ring for driver compatibility and stability, particularly on systems with third‑party camera stacks or imaging/MFP software. Driver updates can interact with vendor camera utilities or capture toolkits; phased rollout reduces the chance of large‑scale breakage.
• Deploy patches to production once validated. Treat hosts with high user counts or high trust (VDI, RDP servers, admin workstations) as top priority.

Important operational caution: some third‑party CVE trackers list multiple related UVC/usbvideo driver issues under different CVE numbers in the same period. This fragmentation can lead to mismatches in KB→CVE mapping; for automation or ticketing always map to Microsoft’s KB name and build level rather than to CVE strings alone.

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Short‑term mitigations when immediate patching is not possible​

If a full patch rollout cannot happen within 24–72 hours, apply compensating controls to reduce exposure:

• Limit local access: enforce least privilege, remove local admin rights where not necessary, and restrict the set of accounts allowed interactive logons on sensitive hosts.
• Block or restrict USB device use on critical hosts: enforce USB device whitelisting or use Device Installation Restrictions (Group Policy) to prevent unknown devices from being installed. For high‑security endpoints, consider disabling USB ports or implementing hardware port locks.
• Enable Memory Integrity / HVCI (Hypervisor‑protected Code Integrity) where feasible — this raises the bar for kernel‑level tampering and complements driver blocklists.
• Enforce Microsoft’s Vulnerable Driver Blocklist (driver blocklisting) and apply application control policies (WDAC/AppLocker) to reduce the chance of untrusted drivers or tooling being loaded.
• Harden logging and telemetry: make sure EDR is capturing kernel‑level events and that you retain memory‑relevant telemetry (process creation, IOCTL calls to kernel drivers, unusual URB/control transfer activity). Behavioral detection is often more effective for kernel info‑leaks than signature detection.

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Detection recommendations (hunting and telemetry)​

A focused hunt can reduce dwell time and surface attempted exploitation before it matures into a more severe compromise. Recommended telemetry and detection points:

• Monitor unusual or repeated IOCTLs and control‑transfer sequences directed at usbvideo.sys or UVC device interfaces. High‑volume, repeated calls or unexpected parameters warrant investigation.
• Alert on processes that request or receive diagnostic/error output from kernel drivers unusually often, or processes that attempt to read device descriptors outside normal behavior.
• Look for anomalous kernel memory disclosure behavior: unexpected memory dumps, small, intermittent reads of kernel structures, or processes that suddenly obtain privileged handles they should not.
• Retain EDR traces and, when suspicious activity is found, collect a memory image quickly (volatile evidence is critical for kernel‑adjacent investigations). If exploitation is suspected, escalate to forensic analysis to determine whether leaked content contained credentials or tokens.

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Deeper technical analysis — why an error message leak is dangerous​

Error messages are a common but under‑appreciated information channel. Developers sometimes include diagnostic content for troubleshooting (stack snippets, pointer values, buffer contents). When that output crosses the kernel/user boundary without sanitization, the attacker can harvest:

• Kernel pointers (useful for bypassing KASLR and ASLR mitigations).
• Sensitive string content, configuration blobs, or small private keys cached in kernel memory by other subsystems.
• Token fragments, handle values, or internal state that assist in elevation or process impersonation.

This CWE‑209 class vulnerability therefore has outsized practical impact: while it does not itself permit code execution, the leaked information is often what transforms a hard exploit into a reliable, scripted local escalation. Treating error messages as a trusted communications channel is a dangerous programming assumption in kernel code; Microsoft’s advisory indicates exactly that type of coding failure occurred here.

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Strengths and weaknesses of the vendor response​

Strengths:

• Microsoft cataloged the issue and published a remediation path in the Security Update Guide, aligning with industry best practice for coordinated disclosure and patch distribution. Public tracking sites have mirrored the advisory, and a patch is available.
• The advisory indicates Microsoft recognizes the confidentiality impact and has assigned a CVSS vector and CWE classification, which helps defenders prioritize remediation.

Weaknesses / operational friction:

• The MSRC Update Guide’s dynamic, client‑rendered interface complicates automated scraping; many automation pipelines and third‑party feeds lag or fragment CVE→KB mappings. This fragmentation can cause mis‑applied patches or gaps in coverage across large estates. Administrators must manually confirm KB IDs for their OS builds in an interactive browser or the Microsoft Update Catalog before automating deployments.
• Microsoft’s public advisory text for kernel info‑leaks is often intentionally terse; while this reduces the risk of providing exploit recipes to attackers, it forces defenders to rely on internal testing and broader mitigations (driver blocklists, memory integrity) rather than rich technical indicators.

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Actionable checklist for IT teams (ordered, practical)​

• Immediately identify hosts with UVC‑enabled devices or which accept USB device attachments and prioritize them for rapid patch validation.
• Confirm the specific KB article(s) Microsoft lists for CVE‑2025‑55676 on the Security Update Guide and the Microsoft Update Catalog. Do not rely solely on a CVE name from third‑party mirrors.
• Stage the vendor update in a pilot ring; specifically test camera utilities, conferencing stacks, and imaging software that interacts with UVC drivers.
• Deploy the patch to production after validation; track successful install and reboots across the estate.
• If immediate patching is not feasible, apply mitigations: restrict USB access, enable Memory Integrity/HVCI, apply the Vulnerable Driver Blocklist, and harden endpoint controls (WDAC/AppLocker, EDR).
• Hunt for suspicious IOCTL/control‑transfer behavior and retain EDR telemetry for at least the window spanning the advisory publication and the patch rollout.
• Validate post‑patch: perform targeted scans to confirm vulnerable driver versions are no longer present and that no unusual driver rollbacks have occurred.

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Risks and long‑term recommendations​

• Driver complexity and legacy code paths keep UVC/usbvideo.sys a recurrent risk area; adopt a persistent posture that mixes timely patching, application control, and device security policies.
• Consider organizational controls to limit physical device attack vectors: restrict USB ports on sensitive hosts, maintain device allow‑lists, and monitor for new device installs.
• Keep high‑fidelity telemetry and proactive hunting capabilities. Information leaks are often exploited in multi‑stage intrusions; robust detection reduces the attacker’s window for leveraging leaked artifacts.

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What could not be independently verified (and why it matters)​

• The public advisory text for CVE‑2025‑55676 is intentionally brief and does not publish a detailed exploit recipe or full IOCs; that is by design to limit risk. Where third‑party mirrors add context, they generally derive their summary from the MSRC entry. Because the Update Guide is delivered as a dynamic app, some external indexers may show partial data; verify KB names in an interactive browser or the Update Catalog before finalizing automation. This limitation raises the need for defenders to rely on vendor KB mapping rather than on external CVE mirrors alone.
• There are no widely published proof‑of‑concept exploits for CVE‑2025‑55676 at the time of reporting. Public trackers show the vulnerability as patched and not currently evidenced in large‑scale exploitation feeds, but the absence of public PoCs is not a guarantee of no exploitation. Treat the lack of public PoC as lower immediate risk, not no risk.

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Conclusion — practical editor’s judgement​

CVE‑2025‑55676 is a confirmed, vendor‑acknowledged information‑disclosure vulnerability in the Windows USB Video Class System Driver with a medium CVSS score and a local attack vector that can meaningfully increase adversary capability when chained with other local exploits. The right operational response is clear and immediate:

• Confirm the MSRC advisory’s KB mappings for your platform(s).
• Patch promptly following standard test→pilot→production rollout procedures.
• Apply compensating mitigations (USB restrictions, HVCI/Memory Integrity, driver blocklist) where patching must be delayed.
• Maintain high‑fidelity telemetry and hunt for suspicious kernel‑adjacent behavior during and after the rollout.

Kernel information leaks may appear less immediately catastrophic than remote code execution flaws, but they often provide the missing piece that turns a local foothold into full host compromise. For that reason, defenders and administrators should treat CVE‑2025‑55676 as operationally important and remediate it prudently and promptly.

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Source: MSRC Security Update Guide - Microsoft Security Response Center