Windows CDPSvc Use-After-Free Elevation to SYSTEM (CVE-2025-54102) – Patch Now

A use‑after‑free vulnerability in the Windows Connected Devices Platform Service (CDPSvc) has been cataloged by Microsoft as an elevation‑of‑privilege issue that can let an authorized, local attacker escalate to SYSTEM, and administrators should treat it as a high‑priority patching item while validating exposure across their fleets. (msrc.microsoft.com)

Background / Overview​

The Connected Devices Platform Service (CDPSvc) is a background Windows service responsible for a range of device‑connectivity features — including Nearby Sharing, Bluetooth and IoT device brokering, and other device‑to‑system interactions. Because CDPSvc runs with elevated privileges on most Windows installations, memory‑corruption bugs in the component can yield powerful escalation paths when exploited. (zeropath.com)
In plain terms, the vulnerability class here is use‑after‑free (UAF): CDPSvc at some point frees memory while a pointer to that memory remains in use. Under the right timing and input conditions (frequently involving race/synchronization behavior) an attacker can cause the service to reuse that freed memory in a way that leads to arbitrary code or control‑flow manipulation at elevated privilege. Public vulnerability trackers and vendor advisories describe the flaw as memory corruption with contributing race conditions. (app.opencve.io)
A patch addressing the issue was distributed as part of Microsoft’s security updates; many public trackers tie the fix to the July 2025 cumulative updates. Administrators should confirm the exact KB/build applicable to their OS SKUs and apply vendor updates in their patch pipelines immediately.

---

What the advisory says — short, authoritative summary​

• Microsoft classifies the bug as “Use after free in Windows Connected Devices Platform Service” and describes it as allowing an authorized local attacker to elevate privileges. (msrc.microsoft.com)
• Public vulnerability records for related CDPSvc issues list the bug under several tracker IDs in the July 2025 update period (examples in public databases include similarly worded entries and high‑severity scores). Administrators should rely on the MSRC advisory and the Microsoft Update Catalog for authoritative build/KB mapping for their environment. (app.opencve.io, nvd.nist.gov)

Note: There is a degree of fragmentation in third‑party trackers where multiple CDPSvc CVE entries appear across July–August 2025; mapping a specific CVE ID to your patch‑management automation requires consulting the vendor advisory and KB list for your exact build. Treat CVE numbers as useful identifiers, but verify the exact KB/build reference from Microsoft for enforcement.

---

Technical analysis — how the flaw works​

Use‑After‑Free, race conditions, and CDPSvc internals​

A use‑after‑free occurs when an object or memory buffer is deallocated while a live reference still exists. In the CDPSvc context this typically happens around device discovery, pairing, or brokered device interactions where objects are created and destroyed rapidly. If an attacker can control the timing — or can supply crafted inputs that alter lifecycle ordering — the freed region can be reallocated with attacker‑controlled data and the dangling pointer dereference then leads to undefined behavior. That undefined behavior can range from program crashes to hijacked execution flow. (zeropath.com, app.opencve.io)
Race and synchronization weaknesses (CWE‑362) often compound UAF bugs: a benign timing window becomes exploitable when concurrently running threads or asynchronous callbacks do not properly coordinate object lifetimes. These characteristics make some UAF bugs easier to weaponize and give them higher severity despite a local attack vector. (app.opencve.io)

Exploitability and attack prerequisites​

• Local, authenticated access: The vulnerability requires the attacker to be able to run code or otherwise interact locally with the target system. It is not a remote, unauthenticated wormable vector in its typical description. This limits the immediate external network risk, but does not diminish the severity — local elevation vulnerabilities are frequently chained with initial access techniques (phishing, untrusted software execution, or a prior foothold) to achieve full compromise. (zeropath.com)
• Privileges required: Public scoring for related CDPSvc UAF bugs has placed the base privilege requirement at low (i.e., a standard user account can be the starting point). That makes the bug particularly attractive once an adversary has any code execution ability as a regular user. (app.opencve.io)
• Complexity: While UAF exploitation often requires precise timing and some local orchestration, modern exploit toolkits and skilled operators can reliably exploit such conditions; historically these vulnerabilities are weaponized quickly once public proof‑of‑concepts appear.

Impact if exploited​

A successful exploit will typically let the attacker obtain NT AUTHORITY\SYSTEM privileges — effectively full control over that host. That enables disabling security tooling, installing persistence mechanisms, dumping secrets, and spreading laterally. Because CDPSvc is present on most client and server SKUs, unpatched fleets are at material risk. (app.opencve.io)

---

Affected systems and severity​

Multiple public vulnerability inventories and Microsoft’s July 2025 update set show CDPSvc fixes applying broadly across supported Windows client and server builds. Examples from independent trackers indicate affected Windows 10, Windows 11, and Server SKUs prior to the July cumulative updates; specific version cutoffs are published per KB for each product. Administrators should not assume any Windows SKU is exempt — verify your build against the MSRC advisory and the update catalog. (app.opencve.io, nvd.nist.gov)
Many third‑party aggregators show a CVSS v3.1 base score in the High range (for related CDPSvc UAF entries a common vector string yields a 7.8 base score), reflecting high confidentiality/integrity/availability impact even though the attack vector is local. Use the vendor advisory for the final authoritative scoring and to inform SLA/priority decisions. (app.opencve.io)

---

Detection, telemetry, and forensic signals​

UAF exploitation is often noisy and may present observable signals before or after a successful escalation. Monitoring and telemetry can give defenders early warning:

• Service crashes and event log noise: Repeated crashes of CDPSvc (or related Service Control Manager errors) are suspicious. Check Windows Event Viewer under Application and System logs for repeated cdpsvc.exe failures, Application Error events, or svchost crash signatures.
• Unusual SYSTEM process activity: After a successful local EoP, you may see unexpected processes running as SYSTEM, sudden scheduled task or service registrations, or abnormal token manipulations. EDR telemetry is critical to correlate process lineage with CDPSvc instability.
• Memory‑corruption indicators: EDRs that surface memory tampering, suspicious heap behavior, or evidence of process injection in svchost‑hosted services should be tuned to alert on CDPSvc activity anomalies.

Hunt guidance (examples):

• Query for recent Service Control Manager (SCM) events referencing CDPSvc.
• Search for application errors pointing at cdpsvc.exe or svchost instances hosting CDPSvc.
• Flag new scheduled tasks, services, or unexpected SYSTEM processes following a CDPSvc crash window.

---

Emergency mitigations and recommended patching playbook​

Patching is the correct long‑term fix. But when patching cannot be completed immediately, choose mitigations that balance business impact and security.

Highest‑priority action (apply vendor fixes)​

• Confirm the MSRC advisory and download the appropriate cumulative update (LCU) and Servicing Stack Update (SSU) for each affected build. Apply through your normal management tooling (Windows Update, WSUS, SCCM/ConfigMgr, Microsoft Intune, or manual package deployment). Reboot if required. (msrc.microsoft.com)
• Update offline images and golden images before redeployment so newly imaged machines are not reintroduced as vulnerable. Use DISM/image servicing workflows to inject the July cumulative packages into images.

Temporary, stopgap mitigation (test first)​

• If an environment can tolerate the loss of device‑connectivity features (Nearby Sharing, certain Bluetooth workflows), you can temporarily stop or disable CDPSvc on non‑production or highly‑segmented hosts while patches are deployed. Example PowerShell commands:
• Stop‑Service -Name CDPSvc -Force
• Set‑Service -Name CDPSvc -StartupType Disabled
• To re‑enable after patching: Set‑Service -Name CDPSvc -StartupType Manual; Start‑Service -Name CDPSvc
  Note: Disabling CDPSvc can break user workflows. Test carefully and document rollback plans.

Verification and validation steps (post‑patch)​

• Validate the build number: Run winver or PowerShell: (Get‑CimInstance Win32_OperatingSystem).BuildNumber.
• Confirm LCU/SSU presence: Use Get‑HotFix or DISM /Online /Get‑Packages to ensure the July 2025 packages are installed.
• Re‑scan with your vulnerability scanner/MDM to ensure the CVE no longer shows as present.

---

Practical step‑by‑step remediation checklist (for admins)​

• Inventory: Build a list of endpoints and servers by OS build, highlighting those with outdated cumulative updates. Use your endpoint management tooling to automate this.
• Prioritize: Start with high‑risk targets — admin workstations, RDP hosts, jump boxes, and servers where users can log in.
• Stage and test: Deploy updates to a staged group before wide rollout to catch any regressions.
• Deploy: Use your normal patch pipeline to push July 2025 LCUs/SSUs across the estate. Monitor update success and reattempt failed installations.
• Validate: Reboot where required, confirm service state, and re‑scan with vulnerability tools.
• Harden: Enforce least privilege and application control (AppLocker / Windows Defender Application Control) to reduce the chance of local code execution by untrusted programs.

---

Risk assessment — strengths, weaknesses, and the operational picture​

Strengths (what protects you)​

• Vendor patch available: Microsoft published updates that remediate the issue, so organizations have a direct remediation path. Administrators who maintain rapid update cadences can neutralize the risk quickly. (msrc.microsoft.com)
• Local vector limits remote immediate risk: Because exploitation requires local access, external attackers without initial access cannot trigger the flaw remotely in typical scenarios. That gives defenders time to react in many cases. (zeropath.com)

Concerns and caveats​

• High impact when chained: Local EoP bugs are frequently the final step in a kill chain: once a foothold exists, these bugs allow full system compromise. That amplifies risk for environments where endpoint defenses are weak or users can run untrusted code.
• Widespread component: CDPSvc is present on many Windows client and server SKUs by default; a large unpatched fleet increases attacker opportunity. (app.opencve.io)
• Version/CVE mapping confusion: Public trackers list multiple related CDPSvc CVEs in the July–August 2025 window (for example, entries with different CVE numbers but nearly identical descriptions appear across trackers). This can complicate automation that matches remediation rules by CVE alone — always map to vendor KB/build guidance rather than relying solely on external aggregator IDs. (cvedetails.com)
• Potential for proof‑of‑concepts: Historically, UAF vulnerabilities see quick PoC publication; once PoCs are public, exploitation becomes easier for many attackers. Treat unpatched systems as high priority.

---

Developer and red‑team perspective (what an attacker would try)​

An attacker who already runs code as a standard user will aim to:

• Trigger CDPSvc operations that create and free objects in a repeatable pattern (device pairing, crafted device responses, or local IPC requests).
• Force a timing window or race where a freed pointer is reused to influence control flow.
• Deploy a payload that escalates privileges to SYSTEM and then launches persistence and lateral movement tools.

This exploitation path is non‑trivial but viable for skilled actors; defenders must assume determined threat actors will attempt these chains when an opportunity exists. (zeropath.com)

---

Questions of CVE numbering and verification​

Multiple public trackers and community advisories in July–August 2025 show several closely related CVEs for Connected Devices Platform Service issues (examples include CVE‑2025‑48000, CVE‑2025‑49724, CVE‑2025‑53721, and others). If you were provided a specific CVE (such as CVE‑2025‑54102), confirm it against Microsoft’s Security Update Guide and the KB references for your OS build; vendor advisories are the authoritative mapping between CVE IDs and KB packages. When automated tooling relies solely on third‑party aggregators, mismatches happen — always validate with the MSRC advisory and Update Catalog before taking enforcement action. (msrc.microsoft.com)
If a CVE ID cannot be found in multiple independent sources, flag it as unverifiable pending vendor confirmation and treat the underlying component exposure (CDPSvc) as the actionable item — patch the component according to the vendor guidance rather than chasing a potentially miscited CVE string.

---

Longer‑term controls to reduce local EoP risk​

• Enforce least privilege: Move users away from local admin accounts and restrict the ability to run arbitrary installers.
• Adopt application allow‑listing: AppLocker or Windows Defender Application Control reduces the chance an untrusted binary can execute.
• Harden endpoint management: Tight patch windows for OS and platform services, and staged updates with rapid rollback plans.
• Monitor for local anomalous behavior: EDR hunt playbooks that focus on process ancestry, service crashes, and SYSTEM token changes will surface chained exploitation attempts earlier.

---

Executive summary and call to action​

• The Windows Connected Devices Platform Service contains a use‑after‑free vulnerability that allows authorized local users to elevate privileges to SYSTEM — a high‑impact, actionable flaw. (msrc.microsoft.com, app.opencve.io)
• Microsoft’s updates (released in the July 2025 cumulative update cycle) contain the patch; apply the appropriate LCU/SSU for each build immediately and update images before redeploying.
• If you cannot patch immediately, consider controlled disabling of CDPSvc where business impact is acceptable, and prioritize monitoring for CDPSvc crashes and related post‑crash SYSTEM activity. Test any mitigation in a small group before widescale rollout.
• Because public trackers have shown multiple nearby CVE entries for similar CDPSvc flaws, validate the exact CVE→KB mapping with Microsoft’s Security Update Guide rather than relying solely on third‑party aggregators. Flag any CVE IDs that cannot be corroborated by the vendor as unverifiable until the vendor confirms. (msrc.microsoft.com)

---

This vulnerability is a reminder that foundational platform services that bridge user interactions and privileged system code remain critical attack surfaces. Rapid patching, disciplined image hygiene, least‑privilege policies, and tuned detection playbooks together provide the best defense against local elevation‑of‑privilege chains that begin with seemingly minor footholds.

---

Source: MSRC Security Update Guide - Microsoft Security Response Center