CVE-2025-55677: Windows Device Association Broker Local Privilege Escalation

Microsoft has assigned CVE-2025-55677 to a newly disclosed elevation-of-privilege vulnerability in the Windows Device Association Broker Service: the vendor describes the root cause as an untrusted pointer dereference that lets an authorized local user escalate privileges, and Microsoft has published updates to address the issue on October 14, 2025.

Background / Overview​

The Device Association Broker Service (part of the Connected Devices/Device Association infrastructure) is responsible for brokering interactions between Windows and external devices and device-related features. It runs with elevated privileges on typical Windows installations, which is why memory- and pointer-safety defects in this service can produce high-impact local elevation-of-privilege (EoP) outcomes. Security advisories for related Connected Devices Platform (CDP) and Device Association components in 2025 show these services are widely present across Windows client and server SKUs, increasing potential blast radius when a privileged service exposes a memory-safety flaw.
Microsoft’s published entry for CVE-2025-55677 classifies the issue as a local EoP that arises from an untrusted pointer dereference (CWE‑822). The initial public metadata reports a CVSS v3.1 base score of 7.8 (High) and indicates the attack vector is local — an attacker must be able to execute or cause code to run on the target machine before escalation can occur.

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What the vulnerability technically is​

Untrusted pointer dereference explained​

An untrusted pointer dereference occurs when privileged code treats a pointer or object reference as valid without sufficiently validating its provenance or contents, and then dereferences it. In privileged services that accept or marshal input from less‑trusted contexts (user sessions, device drivers, or IPC endpoints), an attacker who can control the pointer value or the timing of its use can cause the service to access attacker-controlled memory or objects. That access can lead to memory corruption, control-flow hijacking, or the manipulation of security-critical data — all standard precursors to privilege escalation. Microsoft’s advisory maps CVE‑2025‑55677 to this exact class of weakness (CWE‑822).

How exploitation would be chained in practice​

• The attacker obtains a local foothold (standard user account or ability to run code in a user session).
• They craft input or manipulate IPC/device interactions that cause the Device Association Broker to dereference an attacker-controlled pointer or stale object.
• The dereference leads to memory corruption or unauthorized access paths that the exploit converts into token or context manipulation, allowing impersonation of NT AUTHORITY\SYSTEM or similar privileged identity.

Because the vulnerable service runs with elevated privileges, successful exploitation typically yields SYSTEM-equivalent control on the host, enabling persistence, protection removal, credential access, or lateral movement. This is consistent with the attack model for prior brokering/CDP EoP bugs observed across 2025.

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Confirmed facts and what remains unverified​

• Confirmed by vendor: CVE‑2025‑55677 exists, is categorized as an elevation-of-privilege issue in the Windows Device Association Broker Service, and Microsoft has published remedial updates. The MSRC advisory lists the vulnerability and the vendor-provided update guidance.
• Confirmed technical detail: vendor-classified weakness is untrusted pointer dereference (CWE‑822).
• Reported scoring: CVSS v3.1 base score 7.8 (High) in public aggregators.

Caveats / unverifiable items:

• At the time Microsoft published its advisory there is no authoritative vendor statement that public proof-of-concept (PoC) exploit code exists in the wild. Multiple third‑party aggregators also report no confirmed public PoC or confirmed in-the-wild exploitation for this CVE at publication time, but that status can change quickly after disclosure. Treat any third‑party PoC claims with caution until validated by multiple independent sources or vendor disclosure.
• Product/build mapping: some aggregators list affected OS families in general terms, but authoritative KB / build mapping should come from Microsoft’s Security Update Guide and the Microsoft Update Catalog for your exact SKU. Do not rely on third‑party CVE lists alone when automating patch rollouts.

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Impact and exploitability assessment​

Severity and CVSS interpretation​

Public scoring that accompanies CVE‑2025‑55677 indicates a High severity (CVSS 7.8). The vector is local (AV:L), with low attack complexity in public representations — meaning that once an attacker has local code execution they may not need exotic conditions to exploit the defect. The impact components are shown as high for confidentiality, integrity, and availability in aggregator summaries, reflecting the practical consequences of SYSTEM-level compromise.

Practical attacker prerequisites​

• Local presence on the host — a process running as a standard user or an ability to run code in the target account context.
• Capability to interact with the Device Association Broker input paths (device pairing/IPC/requests the broker services handle).
• Some technical skill to craft conditions that trigger the untrusted pointer dereference and convert the resulting corruption to privilege gain — though historical brokering service bugs show these patterns can sometimes be made reliable with modest effort.

Likely exploitation timeline and risk​

• Short-term: if no public PoC exists at disclosure, immediate risk is lower but still non-trivial because EoP bugs are highly valuable to attackers and can be weaponized once details are circulated.
• Medium-term: if a PoC is published or reverse-engineered from patched code, exploitation likelihood rises rapidly; attackers frequently adapt PoCs into automated toolsets and commodity malware.
• Operational impact: high for unpatched fleets, especially in environments where users have local admin or where privileged services are broadly exposed.

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Affected products and patching guidance​

• Microsoft’s Security Update Guide entry for CVE‑2025‑55677 is the canonical source for exact KB numbers and build mappings for each affected SKU. Public aggregators may report OS families but often lag or fragment; thus, map the CVE to the vendor KB before automated enforcement.
• Some third‑party feeds indicate Microsoft has released patches covering modern Windows 11 and Server SKUs (examples cited by aggregators include Windows 11 24H2/25H2 and Windows Server 2025 family mentions), but verify the exact KB for your environment in the Microsoft Update Catalog. Do not assume a single CVE→KB mapping will match every Windows build.

Recommended immediate actions for administrators (priority list)

• Identify exposed and high‑value systems: query inventory tools for endpoints and servers where Device Association Broker services run and list current build/KBs.
• Map CVE→KB: use Microsoft’s Security Update Guide and your patch-management console (WSUS, SCCM, Intune, or vendor tooling) to find the exact update that addresses CVE‑2025‑55677 for each OS SKU.
• Test the patch in a representative lab before broad rollout to avoid unexpected regressions.
• Deploy updates on a prioritized schedule: internet‑facing or admin workstations first, then general endpoints.
• If immediate patching is impossible: apply layered mitigations (see next section).

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Temporary mitigations and hardening when patch rollout is delayed​

The vendor-supplied update is the definitive fix. If you cannot immediately deploy the patch across your estate, consider compensating controls:

• Restrict local privilege: remove unnecessary local admin rights, and enforce least-privilege practices for interactive users.
• Limit interactive access: restrict RDP and other interactive sessions to management networks and jump hosts.
• Application allow‑listing: deploy Windows Defender Application Control (WDAC) / AppLocker to reduce the attack surface for user-launched exploitable binaries.
• Network segmentation: isolate high‑value hosts and management consoles to reduce the chance of attacker pivoting after an initial foothold.
• Increase telemetry: tune EDR/endpoint logging for service crashes, suspicious process lineage, token modifications, and creation of services/scheduled tasks running as SYSTEM.

Caveat: disabling the Device Association Broker Service is generally unsupported and may break dependent functionality. Only consider unsupported service removal as a last resort and after acceptance testing. Prefer containment and patching whenever feasible.

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Detection and hunting guidance​

Useful telemetry and hunting signals that indicate attempted exploitation or post‑exploit activity:

• Repeated crashes, restarts, or instability of the Device Association Broker service or related CDP processes. Correlate those events with user sessions invoking device-pairing or peripheral interactions.
• Event log patterns: Service Control Manager (SCM) crash events, abnormal termination codes, or correlated application errors.
• Process lineage anomalies: a user-level process spawning a child that performs privileged operations, creates scheduled tasks as SYSTEM, or attempts service/driver installation.
• Suspicious token operations: EDR alerts for token duplication, token impersonation, or attempts to adjust process privileges.
• Unexpected hive writes or changes to HKLM keys and service binary paths attributed to non‑admin users.

Operational note: collect volatile data (memory images, EDR timelines, and event logs) before remediation when you suspect exploitation; evidence gathering is time‑sensitive and critical for post‑incident analysis.

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Practical checks and short commands (examples)​

• Check Device Association Broker service status:
• Get-Service -Name DeviceAssociationBroker
• List installed security updates:
• wmic qfe get HotFixID,Description,InstalledOn
• Search for recent service crashes (example PowerShell):
• Get-EventLog -LogName System -Source Service Control Manager -After (Get-Date).AddDays(-7) | Where-Object {$_.Message -like "Device Association"}
• Export installed KBs via PowerShell (example):
• Get-HotFix | Select-Object HotFixID, InstalledOn

Adapt commands for your environment and management tooling before running at scale. These are illustrative examples used widely in community guidance for similar Windows EoP incidents.

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Risk analysis — strengths, weaknesses, and strategic implications​

Strengths (factors that reduce immediate systemic risk)​

• Vendor remedy exists: Microsoft published updates and guidance tied to the CVE; organizations have an authoritative remediation path.
• Local vector: CVE‑2025‑55677 is not described as remotely exploitable without a local foothold, which reduces mass‑worm risk. That still leaves the vulnerability highly useful in multi-stage attacks, but it narrows the initial exposure model.

Weaknesses and exposures​

• Ubiquity of the service: Device brokering/Connected Devices components ship broadly across Windows SKUs, increasing the unpatched population risk if rollout lags.
• Chaining potential: EoP bugs are common building blocks in sophisticated campaigns—an attacker who gains local execution via phishing, malicious attachment, or browser escape can leverage this CVE to obtain SYSTEM and remove protections or persist.
• CVE→KB fragmentation: third‑party aggregator fragmentation in 2025 created confusion in prior Windows advisories; administrators must rely on Microsoft’s Security Update Guide for authoritative mapping to avoid incomplete patching.

Strategic implications​

• Improve CVE→KB mapping in patch automation to avoid missing patches when third‑party feeds fragment or lag.
• Re-evaluate the business need for always‑on, privileged convenience services. Where feasible, reduce attack surface by constraining or disabling nonessential features with elevated privileges.
• Strengthen least‑privilege and application control policies to reduce the frequency and impact of local code execution events.

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What defenders should communicate internally​

• Treat CVE‑2025‑55677 as a high-priority remediation item even though the initial vector is local. The potential impact (SYSTEM compromise) and the service’s prevalence make this an enterprise concern.
• Map the CVE to the exact KB/build for your OS SKUs using the Microsoft Security Update Guide and your patching tooling before mass deployment or automated enforcement. Relying solely on third‑party CVE lists risks incomplete coverage.
• Prepare incident response playbooks for immediate evidence collection (memory, EDR timelines, event logs) should signs of exploitation appear, and prioritize patch deployment to high-value assets first.

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Final assessment and cautionary note​

CVE‑2025‑55677 is a real and actionable local elevation-of-privilege vulnerability in a privileged Windows service. The vendor-classified weakness (untrusted pointer dereference) and the reported CVSS rating reflect the potential for serious host compromise when combined with an initial local foothold. Microsoft published updates on October 14, 2025; administrators should map the CVE to the vendor KB for their environment, test the patch, and deploy rapidly.
A cautionary point: third‑party aggregators and community writeups sometimes conflate similar brokering/CDP CVEs (memory corruption, UAF, type‑confusion) across the 2025 patch cycles. When you see overlapping CVE numbers or differing technical classifications in public feeds, rely on Microsoft’s Security Update Guide and the Update Catalog for canonical mapping and the definitive remediation artifacts. If you encounter an unvetted PoC, treat it as potentially dangerous and validate provenance before executing it in any test environment.

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By following the prioritized triage checklist (inventory → map CVE to KB → test → deploy → increase telemetry) and applying compensating controls where necessary, organizations can contain the operational risk posed by CVE‑2025‑55677 while ensuring forensic readiness in the unlikely event of exploitation.

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Source: MSRC Security Update Guide - Microsoft Security Response Center