CriticalCVE-2026-85880

    Windows Advanced Local Procedure Call (ALPC) Elevation of Privilege Vulnerability (CVE-2026-85880)

    Published Last modified In CISA KEV since Sources: CVE.org, Msrc Update Guide, pwn.watch, BSI

    What is affected, what to do

    Heap-based buffer overflow in Windows ALPC allows an authorized attacker to elevate privileges locally.

    The vulnerability is being actively exploited; treat it as a priority. Update Microsoft Windows 10 Version 1607 to version 10.0.14393.9512, Microsoft Windows 10 Version 1809 to version 10.0.17763.9245, Microsoft Windows 10 Version 21H2 to version 10.0.19044.7725. Immediate actions, mitigation and detection rules are in the runbook below.

    Affected
    • Microsoft Windows 10 Version 1607 lt 10.0.14393.0..10.0.14393.9512
    • Microsoft Windows 10 Version 1809 lt 10.0.17763.0..10.0.17763.9245
    • Microsoft Windows 10 Version 21H2 lt 10.0.19044.0..10.0.19044.7725
    • Microsoft Windows 10 Version 22H2 lt 10.0.19045.0..10.0.19045.7725
    • Microsoft Windows Server 2012 lt 6.2.9200.0..6.2.9200.26349
    • Microsoft Windows Server 2012 (Server Core installation) lt 6.2.9200.0..6.2.9200.26349
    • Microsoft Windows Server 2012 R2 lt 6.3.9600.0..6.3.9600.23398
    • Microsoft Windows Server 2012 R2 (Server Core installation) lt 6.3.9600.0..6.3.9600.23398
    • Microsoft Windows Server 2016 lt 10.0.14393.0..10.0.14393.9512
    • Microsoft Windows Server 2016 (Server Core installation) lt 10.0.14393.0..10.0.14393.9512
    • Microsoft Windows Server 2019 lt 10.0.17763.0..10.0.17763.9245
    • Microsoft Windows Server 2019 (Server Core installation) lt 10.0.17763.0..10.0.17763.9245
    • Microsoft Windows Server 2022 lt 10.0.20348.0..10.0.20348.5622
    Fixed in
    • Microsoft Windows 10 Version 1607 10.0.14393.9512
    • Microsoft Windows 10 Version 1809 10.0.17763.9245
    • Microsoft Windows 10 Version 21H2 10.0.19044.7725
    • Microsoft Windows 10 Version 22H2 10.0.19045.7725
    • Microsoft Windows Server 2012 6.2.9200.26349
    • Microsoft Windows Server 2012 (Server Core installation) 6.2.9200.26349
    • Microsoft Windows Server 2012 R2 6.3.9600.23398
    • Microsoft Windows Server 2012 R2 (Server Core installation) 6.3.9600.23398
    • Microsoft Windows Server 2016 10.0.14393.9512
    • Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.9512
    • Microsoft Windows Server 2019 10.0.17763.9245
    • Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.9245
    • Microsoft Windows Server 2022 10.0.20348.5622

    Not sure whether and how you are affected? Ask a question about this vulnerability

    Metrics

    7.8

    Priority

    XIEM Effective CVSS: highest available CVSS rating from NVD and vendor data.

    Source: NVD, CVSS v3

    7.8

    CVSS v3

    Severity High on the scale from 0 to 10.

    Source: CVE.org, Msrc Update Guide, pwn.watch, BSI

    0.4 %

    EPSS score

    Low — model estimates < 1% exploitation likelihood.

    Source: FIRST EPSS, percentile 32.6

    Show all metrics
    Severity
    Critical
    Priority (0–325)

    The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?

    Read in glossary
    229.88 Methodology
    Exploit maturity

    An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.

    Read in glossary
    actively exploitedSource: VulnCheck KEV (opens in a new tab) How we classify
    XIEM Effective CVSS

    XIEM® is the tiered managed-security operating model from NEOSEC and a registered trademark of NEOSEC GmbH. It extends classic SIEM — the central collection, normalisation and correlation of security-relevant events — with endpoint forensics, network visibility and deception technology, and consolidates them into three building tiers: Sentry, Orchestrate and Command.

    Read in glossary
    7.8 Methodology
    CVSS v3

    CVSS is the globally established, open standard for assessing the technical severity of a vulnerability on a scale from 0 to 10. It describes how easily a flaw can be exploited and what damage it can cause — but not how likely its actual exploitation is. CVSS and the complementary EPSS deliberately answer different questions.

    Read in glossary
    7.8
    EPSS score

    The EPSS score is the absolute model output for an individual vulnerability: the estimated probability of real-world exploitation within the next 30 days, expressed as a value between 0 and 1 (i.e. 0 % to 100 %). A score of 0.42 means „the model estimates a 42 % chance of real-world exploitation within 30 days“.

    Read in glossary
    0.4 %
    Low — model estimates < 1% exploitation likelihood.
    EPSS percentile

    The EPSS percentile is the relative position of a vulnerability within all EPSS-scored CVEs, expressed as a value between 0 and 1. A percentile of 0.90 means „this CVE has a higher EPSS score than 90 % of all other scored CVEs“. Unlike the EPSS score, it is not a probability — but a positioning within a ranking.

    Read in glossary
    32.6
    Elevated — this CVE ranks above at least 10% of all CVEs scored today.
    KEV status

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    Actively exploited
    Published
    In CISA KEV since

    The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.

    Read in glossary
    CWE

    CWE is a catalogue of typical weakness types in software and hardware — such as flawed input validation, unsafe memory handling or poor authentication. Where a CVE names a concrete vulnerability in a concrete product, a CWE describes the underlying class of defect.

    Read in glossary
    CWE-122, CWE-908

    Response and mitigation

    Why act now?

    Prioritisation rationale

    Exploitation requires local access with low privileges but no user interaction, and success yields full compromise of the host's confidentiality, integrity and availability — making this a classic second stage after phishing, stolen credentials or a remote code execution foothold. Exploitation likelihood is rated as notably elevated; CISA does not currently flag ransomware use, but that does not lower urgency, since Windows LPEs routinely feature in intrusion chains. Organisations running multi-user hosts, VDI estates or clients without application control should treat this as a high-priority rollout within days; isolated single-user systems with strict privilege management can follow the regular cycle with expedited approval.

    1. Runbook step 1

      Immediate response (0-24 h)

      • Deploy the security update: A patch is available from Microsoft — look up the KB number and the fixed build in the MSRC advisory for CVE-2026-85880. Affected lines per the context: Windows 10 1607 (build 10.0.14393.x), 1809 (10.0.17763.x), 21H2 (10.0.19044.x) and 22H2 (10.0.19045.x). Cross-check the listed builds (14393.9512, 17763.9245, 19044.7725, 19045.7725) against MSRC to confirm whether they mark the last vulnerable or first fixed revision.
      • Inventory by build number: Query Intune/MECM/WSUS or run Get-ComputerInfo | Select OsBuildNumber and read HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\UBR. Because 14393 and 17763 are also the build bases of Windows Server 2016/2019, check whether the MSRC advisory lists server editions too.
      • Patch order: Multi-user systems first (RDS/Citrix hosts, jump servers, VDI), then privileged access workstations and hosts running internet-facing services where an attacker could gain low-privileged code execution; standard clients afterwards.
      • Compromise check on unpatched critical hosts: Hunt the last 14 days for unexpected SYSTEM processes with user-context parents and for bugchecks (Event ID 1001) — see detection rules. On a hit, isolate the host and preserve evidence.
      • Restrict local logon: Until patched, limit interactive and RDP logon on servers and jump hosts to required staff only (GPO "Allow log on locally" / "Allow log on through Remote Desktop Services").
    2. Runbook step 2

      Mitigation layers

      • Application control (endpoint hardening): There is no configurable workaround for ALPC itself. The strongest compensating control is stopping exploit binaries from running: WDAC or AppLocker in enforce mode, blocking execution from user-writable paths (%TEMP%, %APPDATA%, %LOCALAPPDATA%, C:\Users\Public, Downloads).
      • ASR rules (Microsoft Defender): Enable "Block executable files from running unless they meet a prevalence, age, or trusted list criterion" and "Block execution of potentially obfuscated scripts" to hinder staging of LPE tooling.
      • IAM / least privilege: Remove standing local admin rights, use LAPS for local admin accounts, and enforce the tiering model (Tier 0/1/2) so a successful escalation on a workstation does not yield domain credentials.
      • Credential protection: Enable Credential Guard and LSA protection (RunAsPPL) — SYSTEM access is commonly used for LSASS dumping, so this caps the blast radius.
      • Network segmentation: Place unpatched hosts in dedicated VLANs with tight east-west rules (SMB 445, RDP 3389, WinRM 5985/5986 only from admin networks) to limit lateral movement after escalation.
    3. Runbook step 3

      Detection rules

      • Integrity-level jump in process tree (Sysmon EID 1 / Security 4688): Process running as NT AUTHORITY\SYSTEM / System integrity whose parent runs at Medium integrity and is not services.exe, wininit.exe or svchost.exe. KQL: DeviceProcessEvents | where ProcessIntegrityLevel=="System" and InitiatingProcessIntegrityLevel=="Medium".
      • SYSTEM shells from user paths: cmd.exe/powershell.exe running as SYSTEM with a parent under \Users\ or \ProgramData\. Sigma shape: ParentImage|contains: '\Users\' AND User|contains: 'SYSTEM' AND Image|endswith: ['\cmd.exe','\powershell.exe'].
      • Failed exploitation attempts: A heap overflow in ALPC frequently crashes the host when it fails — correlate System log Event ID 1001 (BugCheck) and Event ID 41 (Kernel-Power) on clients with no hardware fault; repeated crashes on one host are a strong signal.
      • Privilege use and follow-on activity: Security Event ID 4672 (special privileges assigned) for unexpected accounts, plus Sysmon EID 10 with TargetImage=lsass.exe shortly after an integrity jump; triage EDR "token manipulation" / "privilege escalation" alerts with priority.
      • Post-escalation persistence: Security 4697 / System 7045 (new service) and 4698 (scheduled task) on hosts that previously triggered any of the rules above.

    Detection rules

    No NEOSEC detection rule is available for this vulnerability yet.

    Classification under NIS2 and CRA

    Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.

    NIS2

    NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.

    Read in glossary
    Actively exploited: treat the vulnerability as a priority in vulnerability handling under Art. 21(2)(e) NIS2. If it is exploited in your environment, check the reporting obligation under Art. 23 (early warning within 24 hours).
    CRA

    The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.

    Read in glossary
    Since 11.09.2026, manufacturers of affected products with digital elements must report actively exploited vulnerabilities under Art. 14 CRA, with an early warning within 24 hours via ENISA's single reporting platform.
    ISO/IEC 27001

    ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.

    Read in glossary
    Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.

    Description

    Heap-based buffer overflow in Windows ALPC allows an authorized attacker to elevate privileges locally.

    Source: NVD (NIST), CVE.org (MITRE), CISA KEV Catalog, Microsoft Security Update Guide, pwn.watch, cvelistv5, BSI CSAF, BSI WID Portal

    Affected products

    The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

    Affected products
    Affected versionsFixed in
    MicrosoftWindows 10 Version 1607
    • 10.0.14393.0 – < 10.0.14393.9512
    • 10.0.14393.9512
    MicrosoftWindows 10 Version 1809
    • 10.0.17763.0 – < 10.0.17763.9245
    • 10.0.17763.9245
    MicrosoftWindows 10 Version 21H2
    • 10.0.19044.0 – < 10.0.19044.7725
    • 10.0.19044.7725
    MicrosoftWindows 10 Version 22H2
    • 10.0.19045.0 – < 10.0.19045.7725
    • 10.0.19045.7725
    MicrosoftWindows Server 2012
    • 6.2.9200.0 – < 6.2.9200.26349
    • 6.2.9200.26349
    MicrosoftWindows Server 2012 (Server Core installation)
    • 6.2.9200.0 – < 6.2.9200.26349
    • 6.2.9200.26349
    MicrosoftWindows Server 2012 R2
    • 6.3.9600.0 – < 6.3.9600.23398
    • 6.3.9600.23398
    MicrosoftWindows Server 2012 R2 (Server Core installation)
    • 6.3.9600.0 – < 6.3.9600.23398
    • 6.3.9600.23398
    MicrosoftWindows Server 2016
    • 10.0.14393.0 – < 10.0.14393.9512
    • 10.0.14393.9512
    MicrosoftWindows Server 2016 (Server Core installation)
    • 10.0.14393.0 – < 10.0.14393.9512
    • 10.0.14393.9512
    MicrosoftWindows Server 2019
    • 10.0.17763.0 – < 10.0.17763.9245
    • 10.0.17763.9245
    MicrosoftWindows Server 2019 (Server Core installation)
    • 10.0.17763.0 – < 10.0.17763.9245
    • 10.0.17763.9245
    MicrosoftWindows Server 2022
    • 10.0.20348.0 – < 10.0.20348.5622
    • 10.0.20348.5622

    Vendors and products

    Affected operating systems

    Affected operating systems
    Windowsmicrosoftwindows_10_1607—
    Windowsmicrosoftwindows_10_1809—
    Windowsmicrosoftwindows_10_21h2—
    Windowsmicrosoftwindows_10_22h2—
    Windowsmicrosoftwindows_server_2012r2
    Windowsmicrosoftwindows_server_2012—
    Windowsmicrosoftwindows_server_2016—
    Windowsmicrosoftwindows_server_2019—
    Windowsmicrosoftwindows_server_2022—

    Weakness classes (CWE)

    • CWE-122Heap-based Buffer Overflow

      Variant

      A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc().

      Entry at MITRE CWE-122
    • CWE-908Use of Uninitialized Resource

      Base

      The product uses or accesses a resource that has not been initialized.

      Entry at MITRE CWE-908

    Public exploit references

    Publicly reported proof-of-concepts, exploit modules and detection templates for this vulnerability. NEOSEC links to the original sources only and does not provide any exploit code.

    Public exploit references
    CISA KEV CatalogCISA Known Exploited Vulnerability (opens in a new tab)cisa.govactively exploited

    References & sources

    Changes to this CVE

    Who changed this CVE and when: NVD (analysis, affected products, CVSS), the CVE publisher (CNA) and additional providers such as CISA (ADP).

    1. Record modifiedMicrosoft

      1 individual change: Affected versions (publisher)

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Affected versions (publisher)added
      —
      Affected value modified. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/85xxx/CVE-2026-85880.json">CVE-2026-85880</a>

      Source identifier: secure@microsoft.com

    2. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: active, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentchanged
      {"id":"CVE-2026-85880","role":"CISA Coordinator","options":[{"exploitation":"active"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-08T18:44:18.362923Z"}
      {"id":"CVE-2026-85880","role":"CISA Coordinator","options":[{"exploitation":"active"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-08T00:00:00+00:00"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    3. Initial analysis by NVDNVD

      Show 3 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Product configurationadded
      —
      OR *cpe:2.3:o:microsoft:windows_server_2012:r2:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_server_2012:-:*:*:*:*:*:*:* *cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x64:* versions up to (excluding) 10.0.14393.9512 *cpe:2.3:o:microsoft:windows_10_1607:*:*:*:*:*:*:x86:* versions up to (excluding) 10.0.14393.9512 *cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x64:* versions up to (excluding) 10.0.17763.9245 *cpe:2.3:o:microsoft:windows_10_1809:*:*:*:*:*:*:x86:* versions up to (excluding) 10.0.17763.9245 *cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:arm64:* versions up to (excluding) 10.0.19044.7725 *cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x64:* versions up to (excluding) 10.0.19044.7725 *cpe:2.3:o:microsoft:windows_10_21h2:*:*:*:*:*:*:x86:* versions up to (excluding) 10.0.19044.7725 *cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:arm64:* versions up to (excluding) 10.0.19045.7725 *cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x64:* versions up to (excluding) 10.0.19045.7725 *cpe:2.3:o:microsoft:windows_10_22h2:*:*:*:*:*:*:x86:* versions up to (excluding) 10.0.19045.7725 *cpe:2.3:o:microsoft:windows_server_2016:*:*:*:*:*:*:*:* versions up to (excluding) 10.0.14393.9512 *cpe:2.3:o:microsoft:windows_server_2019:*:*:*:*:*:*:*:* versions up to (excluding) 10.0.17763.9245 *cpe:2.3:o:microsoft:windows_server_2022:*:*:*:*:*:*:*:* versions up to (excluding) 10.0.20348.5622
      Reference typeadded
      —
      Microsoft Corporation: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85880 Types: Patch, Vendor Advisory
      Reference typeadded
      —
      CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-85880 Types: US Government Resource

      Source identifier: nvd@nist.gov

    4. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: active, automatable: no

      Show 2 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Referenceadded
      —
      https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-85880
      SSVC assessmentchanged
      {"id":"CVE-2026-85880","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-08T17:38:42.031961Z"}
      {"id":"CVE-2026-85880","role":"CISA Coordinator","options":[{"exploitation":"active"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-08T18:44:18.362923Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    5. CISA KEV entry updated9119a7d8…

      4 individual changes: Date Added, Due Date, Required Action, Vulnerability Name

      Show 4 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Date Addedadded
      —
      2026-09-08
      Due Dateadded
      —
      2026-09-08
      Required Actionadded
      —
      2026-09-08
      Vulnerability Nameadded
      —
      2026-09-08

      Source identifier: 9119a7d8-5eab-497f-8521-727c672e3725

    Show 2 older changes
    1. ReceivedMicrosoft

      CVSS V3.1: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

      Weakness type: CWE-122, CWE-908

      Description added or changed

      Show 6 original changes
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      Descriptionadded
      —
      Heap-based buffer overflow in Windows ALPC allows an authorized attacker to elevate privileges locally.
      CVSSadded
      —
      AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
      Weakness type (CWE)added
      —
      CWE-122
      Weakness type (CWE)added
      —
      CWE-908
      Affected versions (publisher)added
      —
      New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/85xxx/CVE-2026-85880.json">CVE-2026-85880</a>
      Referenceadded
      —
      https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85880

      Source identifier: secure@microsoft.com

    2. Record modifiedCISA ADP

      CISA assessment (SSVC): exploitation: none known, automatable: no

      Show the original change
      Individual changes of this event as published by NVD
      TypeActionBeforeAfter
      SSVC assessmentadded
      —
      {"id":"CVE-2026-85880","role":"CISA Coordinator","options":[{"exploitation":"none"},{"automatable":"no"},{"technicalImpact":"total"}],"version":"2.0.3","timestamp":"2026-09-08T17:38:42.031961Z"}

      Source identifier: 134c704f-9b21-4f2e-91b3-4a467353bcc0

    Linked advisories

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    <a href="https://intel.neosec.eu/en/cve/CVE-2026-85880"><img src="https://intel.neosec.eu/badge/cve/CVE-2026-85880.svg?lang=en" alt="CVE-2026-85880 – NEOSEC Intel" height="20"></a>