CVE-2026-25175: Windows NTFS Local Privilege Escalation via Out-of-Bounds Read

Microsoft’s security catalog lists CVE-2026-25175 as a newly recorded elevation-of-privilege vulnerability in the Windows NTFS file system: an out-of-bounds read in the NTFS driver that, when triggered by a local, low-privileged account, can be converted into a SYSTEM-level compromise. (cvedetails.com) (cvefeed.io)

Background​

NTFS (New Technology File System) is the kernel-mode file system driver that underpins file and metadata handling for the majority of Windows installations. Vulnerabilities in NTFS are high-stakes because the file system runs in kernel context and interacts with untrusted user input—file metadata, paths, and remote shares—making memory-safety bugs particularly dangerous.
CVE-2026-25175 was published on March 10, 2026 and is described by vendor and independent trackers as an out-of-bounds read (CWE-125) in the NTFS implementation that can be abused by a local attacker to elevate privileges. The vulnerability has been assigned a CVSS v3.1 base score of 7.8 (High) with the vector showing local attack but low privileges required and no user interaction. (cvedetails.com) (cvefeed.io)
Microsoft’s Security Update Guide is referenced as the authoritative vendor record for this CVE; some public aggregators and vulnerability databases mirror Microsoft’s short advisory text and scoring while the vendor’s detailed, per-build KB mapping is typically provided by the Security Update Guide itself. Public security-discussion channels and vendor trackers emphasize that Microsoft’s internal *confidnal used by the vendor to indicate how certain they are about a vulnerability’s existence and the credibility of the details) shapes triage and response priorities.

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What the vulnerability is (technical summary)​

At a high level, CVE-2026-25175 is described as an out-of-bounds read in the Windows NTFS driver. An out-of-bounds read occurs when code reads memory beyond the boundaries of an allocated buffer, which can leak kernel memory contents or cause undefined behavior that an attacker can sometimes leverage to escalate privileges.
Key technical points reported in vendor/aggregated records:

• The defect is an out-of-bounds read categorized under CWE-125. (cvefeed.io)
• The issue is locally exploitable: the attack vector is not remote network access but local user actions that interact with NTFS semantics (opening or manipulating files, special metadata, or local mount points). (cvedetails.com)
• The vulnerability’s calculated CVSS attributes indicate low attack complexity, low privileges required, and no user interaction, which together raise operational urgency for any host where low-privileged local accounts are present. (cvedetails.com)

Because the NTFS driver executes in kernel space, an attacker who turns an out-of-bounds read into an information disclosure or memory-corruption primitive may be able to escalate to SYSTEM by combining this bug with other local primitives (e.g., kernel info-leak => bypass of exploit mitigations => code execution). Public trackers currently describe the impact as elevation-of-privilege; however, exact exploitation techniques and proof-of-concept code are not present in the public record at the time of this writing. Multiple vulnerability aggregators mirror Microsoft’s description but do not publish exploit code. (cvefeed.io)

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Why NTFS bugs are especially consequential​

• Kernel privileges: NTFS runs in kernel mode. Any memory-safety fault reached from a subsystem that parses user-controlled file metadata can give attackers a direct path to high-impact outcomes.
• Wide exposure surface: NTFS operates over local filesystem APIs as well as network-shared volumes (SMB) and mounted images. This gives attackers multiple interaction points to craft trigger conditions.
• Low initial access requirement: Because the record lists “Privileges Required: Low,” any scenario that grants a user the ability to create, open, or manipulate files on an affected host can be a sufficient foothold for an attacker to start an exploitation chain. (cvedetails.com)

These attributes make even a single out-of-bounds read in NTFS a high-priority item for enterprise defenders: a local foothold coupled with a kernel exploit is the canonical path to complete system compromise.

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Vendor record and public corroboration​

Microsoft’s Security Update Guide is listed as the canonical vendor reference for CVE-2026-25175; public CVE aggregators (CVE Details, cvefeed, and similar trackers) have ingested the vendor’s short advisory and assigned the CVSS and CWE entries used above. These mirrors confirm the vendor-specified classification (out-of-bounds read, NTFS, elevation-of-privilege) and the March 10, 2026 publication date. (cvedetails.com) ([cvefeed.io](https://cvefeed.io/vuln/detail/CVE-202ommunity discussion and internal incident threads (mirror archives and community forums) track similar NTFS and kernel-mode vulnerabilities and often note the vendor’s “confidence” signal—Microsoft sometimes publishes concise entries that omit exploit-level specifics until customers have had time to deploy updates. That deliberate withholding of low-level details helps limit immediate exploitation but complicates defenders’ ability to hunt for pre-patch exploitation.
Important operational fact: as of the initial publication, mainstream vulnerability mirrors do not show a public proof-of-concept or active-exploitation reports specifically tied to CVE-2026-25175. EPSS (Exploit Prediction Scoring System) entries or exploit feeds do not yet indicate reliable exploitation likelihood for this CVE, though that can change quickly once public technical details or PoCs appear. (cvefeed.io)

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Practical impact scenario — how an attacker might use this​

The canonical attack flow for local kernel EoP issues like CVE-2026-25175 typically follows these steps:

• Obtain local code execution at low privilege (e.g., via malicious user account, untrusted application, or a separate low-privileged exploit).
• Interact with the file system in a way that exercises the NTFS parsing path described by the advisory (the exact file operations will vary; vendor advisories often leave these implementation details out while patches are deployed).
• Trigger the out-of-bounds read to leak kernel addresses, credentials, or internal structures, or to corrupt state in a controlled way.
• Use the information disclosure or state corruption to bypass kernel exploit mitigations and escalate to SYSTEM.

Because the CVSS vector indicates low privileges and no user interaction, the second and third steps can often be scripted or embedded into lateral-movement toolsets—making the vulnerability suitable for post-compromise escalation. This is why organizations must treat local EoP bugs with the same urgency they give to remote code execution flaws whenever high-value, multi-user servers or endpoints are concerned. (cvedetails.com)

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What Microsoft/administrators should be doing now (urgent checklist)​

• Patch immediately: Apply Microsoft’s security updates that map to CVE-2026-25175 as soon as vendor KB guidance is available for the specific OS builds in your environment. The vendor record is the authoritative map for per-SKU updates, and public aggregators link back to Microsoft’s Security Update Guide. Prioritize servers, management hosts, and systems with many low-privileged accounts. (cvefeed.io)
• Inventory exposure: Identify machines where unprivileged users can create/modify files or mount images—this includes multi-user terminal servers, CI/CD agents, developer laptops, file servers, and cloud VM images. Treat those hosts as high priority for patching.
• Short-term hardening: If you cannot patch immediately, reduce the attack surface:
• Restrict local accounts that are not needed.
• Limit who can write to shared folders and trust boundaries.
• Block untrusted file shares and disallow automatic mounting of removable media where possible.
• Monitor and hunt: Deploy detection rules that look for:
• Unexpected NTFS driver crashes and blue screens that reference file-system code paths.
• Quick, scripted filesystem operations from non-standard processes (e.g., a web-browser process writing and executing from unexpected locations).
• Sudden privilege escalations in telemetry and EDR logs.
• Validate updates: After installing vendor patches, verify the OS build and KB IDs; the Security Update Guide and per-build KBs are how Microsoft maps CVEs to installers—do not assume a generic Windows Update has installed the necessary kernel-mode fix until you confirm the KB mapping for the SKU. (cvefeed.io)

Numbered remediation steps for administrators:

• Identify affected SKUs and CVE-KB mapping in Microsoft’s Security Update Guide.
• Schedule emergency patch deployment to high-priority hosts (management servers, domain controllers, multi-user endpoints).
• Apply patches and restart hosts where required.
• Validate the presence of the security update on patched hosts.
• Monitor telemetry and run targeted hunts for unusual NTFS interactions and privilege escalation attempts.

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Detection, telemetry, and hunting guidance (practical)​

Because vendor advisories for kernel-mode issues often omit exploitation details, defenders should rely on behavior and telemetry patterns rather than exact indicators tied to a PoC. Suggested detection primitives:

• Kernel crash patterns: monitor Windows Error Reporting / kernel dump collections for newly occurring NTFS-related bugchecks or repeated crashes from ntfs.sys on multiple hosts.
• File-system anomaly detection: flag processes that perform large numbers of unusual metadata operations (creating complex metadata structures, alternate data streams, reparse points) from non-administrative processes.
• Privilege escalation patterns: track sudden creation of scheduled tasks, service creation, token duplication, or creation of SYSTEM-owned processes where the initiating process was low-privileged.
• EDR correlation: correlate suspicious NTFS activity with prior local compromise signals (malicious process spawn, persistence artifacts) to detect chained exploitation attempts.

Note: public PoC or tailored exploit signatures do not appear to be widely available for CVE-2026-25175 at the time of initial publication; rely on behavioral detections and apply patches to remove the attack opportunity. (cvefeed.io)

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Strengths of the vendor response and community coverage​

• Rapid cataloging: Microsoft’s Security Update Guide listing allows defenders to map affected builds and KBs; public CVE mirrors have already ingested the record and CVSS score, enabling enterprise vulnerability management systems to flag impacted assets. (cvedetails.com)
• Conservative disclosure posture: By not publishing exploit-level details publicly before fixes are widely available, the vendor reduces the short-loitation that often follows full technical dumps.
• Community triage: Multiple independent vulnerability trackers (CVE Details, cvefeed, etc.) corroborate the vendor’s high-level description and severity score, giving defenders cross-checked data points for triage and rule creation. (cvedetails.com) (cvefeed.io)

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Risks, unknowns, and caveats​

• Limited public technical detail: As is common with kernel-mode advisories, the public advisory text is concise. This helps slow immediate exploitation but hurts defenders who need to craft precise detections before patches are applied. Treat all claims about PoCs or exploit mechanics as speculative unless confirmed by multiple, credible technical analyses.
• Local-only vector but low barrier: Although the attack vector is local, the requirement for only low privileges makes this vulnerability an attractive escalation path for attackers who already have a foothold—e.g., through phishing, malicious installers, or other local exploits.
• Potential for rapid weaponization: Historically, kernel vulnerabilities in widely deployed subsystems like NTFS are weaponized quickly once public technical details or exploit code are released. Immediate patching and defensive hardening are therefore essential even if active exploitation is not yet observed. (cvedetails.com)
• Database timing and metadata inconsistencies: Aggregated vulnerability databases (mirrors, trackers) may display metadata slightly differently (EPSS availability, product lists, or CVE mappings) because of ingestion timings. Always use Microsoft’s Security Update Guide as the source of truth for per-build remediation mapping. (cvefeed.io)

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How this fits into the broader pattern of NTFS/kernel vulnerabilities​

NTFS and other kernel-facing drivers have been the subject of numerous memoior months and years. The recurring pattern is familiar: a small parsing error or race in a kernel path that touches user-controlled data can elevate a local foothold to SYSTEM. Attackers and researchers alike focus on file-system edge cases—reparse points, alternate data streams, malformed metadata—because they offer rich, reachable attack surface with complex parsing logic that historically has produced memory-safety issues.
CVE-2026-25175 joins an ongoing set of NTFS-related advisories that defenders have tracked and patched over the last two years; the defensive playbook for file-system kernel bugs—patch quickly, minimize local write capability, and hunt using behavior analytics—remains effective when applied consistently. Community threads and vulnerability summaries from previous NTFS advisories provide practical detection and containment templates that teams can reuse.

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Responsible disclosure and public information: what’s verifiable​

What is verifiable from vendor-tracked and independent sources right now:

• The CVE identifier CVE-2026-25175 is published and tied to an NTFS out-of-bounds read. (cvedetails.com)
• The CVSS v3.1 base score of 7.8 and the CWE-125 classification are recorded in public mirrors://cvefeed.io/vuln/detail/CVE-2026-25175))
• The vendor reference is Microsoft’s Security Update Guide; public aggregators link back to that authoritative entry. (cvefeed.io)

What is not (yet) verifiable from public sources:

• Full technical root cause details (line-level diffs or the exact code path in ntfs.sys triggering the out-of-bounds read) have not been published in the public advisory at time of writing.
• No confirmed, widely accepted proof-of-concept exploit or exploit kit was visible in major public feeds at initial publication; this could change rapidly if researchers or adversaries publish exploits. (cvefeed.io)

Because some vendor pages require client-side rendering and interactive mapping (Microsoft’s Security Update Guide uses a JavaScript-based UI), researchers and defenders should confirm per-build KB mappings using vendor-supplied guidance and administrative portals rather than solely relying on third-party mirrors.

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Bottom line — operational guidance for Windows administrators​

• Treat CVE-2026-25175 as a high-priority local elevation-of-privilege risk and apply the vendor-supplied security updates to all affected systems without delay. (cvefeed.io)
• If immediate patching is impossible, reduce local write/mount privileges, restriolumes, and harden endpoints against local-scripted behavior.
• Use behavioral EDR detections for NTFS anomalies, kernel crashes, and sudden privilege escalation events while you patch.
• Validate KB mappings and test patches in staging before broad rollout, but do not delay remediation on high-value or exposed hosts.
• Maintain situational awareness: monitor exploit feeds and trusted vendor channels for any PoC disclosures, and prioritize any hosts that show signs of pre-existing compromise.

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CVE-2026-25175 is a reminder that memory-safety defects in kernel-facing components remain an acute operational risk for Windows environments. The combination of a kernel-mode target surface (NTFS), a low required privilege level, and a high-impact CVSS score means organizations need both rapid patching discipline and robust behavior-based detection to reduce the window of opportunity for attackers. Apply vendor updates now, validate the fixes, and harden systems to reduce the value of local footholds while you close this gap. (cvedetails.com) (cvefeed.io)

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Source: MSRC Security Update Guide - Microsoft Security Response Center