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
- Microsoft Windows 10 Version 1607
- 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
- Microsoft Windows 10 Version 1607
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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 glossaryCWE
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.
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 OsBuildNumberand readHKLM\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").
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.
- 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 (
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 notservices.exe,wininit.exeorsvchost.exe. KQL:DeviceProcessEvents | where ProcessIntegrityLevel=="System" and InitiatingProcessIntegrityLevel=="Medium". - SYSTEM shells from user paths:
cmd.exe/powershell.exerunning as SYSTEM with a parent under\Users\or\ProgramData\. Sigma shape:ParentImage|contains: '\Users\'ANDUser|contains: 'SYSTEM'ANDImage|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.exeshortly 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.
- Integrity-level jump in process tree (Sysmon EID 1 / Security 4688): Process running as
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 versions | Fixed in | ||
|---|---|---|---|
| Microsoft | Windows 10 Version 1607 |
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| Microsoft | Windows 10 Version 1809 |
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| Microsoft | Windows 10 Version 21H2 |
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| Microsoft | Windows 10 Version 22H2 |
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| Microsoft | Windows Server 2012 |
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| Microsoft | Windows Server 2012 (Server Core installation) |
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| Microsoft | Windows Server 2012 R2 |
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| Microsoft | Windows Server 2012 R2 (Server Core installation) |
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| Microsoft | Windows Server 2016 |
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| Microsoft | Windows Server 2016 (Server Core installation) |
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| Microsoft | Windows Server 2019 |
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| Microsoft | Windows Server 2019 (Server Core installation) |
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| Microsoft | Windows Server 2022 |
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Vendors and products
- Microsoft Microsoft Windows 10 1607
- Microsoft Microsoft Windows 10 1809
- Microsoft Microsoft Windows 10 21H2
- Microsoft Microsoft Windows 10 22h2
- Microsoft Windows 10 Version 1607
- Microsoft Windows 10 Version 1809
- Microsoft Windows 10 Version 21h2
- Microsoft Windows 10 Version 22h2
- Microsoft Microsoft Windows Server 2012
- Microsoft Windows Server 2012 R2
- Microsoft Windows Server 2012 R2 (server Core Installation)
- Microsoft Windows Server 2012 (server Core Installation)
Affected operating systems
| Windows | microsoft | windows_10_1607 | — |
| Windows | microsoft | windows_10_1809 | — |
| Windows | microsoft | windows_10_21h2 | — |
| Windows | microsoft | windows_10_22h2 | — |
| Windows | microsoft | windows_server_2012 | r2 |
| Windows | microsoft | windows_server_2012 | — |
| Windows | microsoft | windows_server_2016 | — |
| Windows | microsoft | windows_server_2019 | — |
| Windows | microsoft | windows_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-122CWE-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.
| CISA KEV Catalog | CISA Known Exploited Vulnerability (opens in a new tab)cisa.gov | actively exploited |
References & sources
- Microsoft Security Update GuideWindows Advanced Local Procedure Call (ALPC) Elevation of Privilege VulnerabilityVendor advisory, Patch
- cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2026-85880government-resource
- pwn.watchpwn.watch: Microsoft Windows: Microsoft Windows Link Following Vulnerabilitypwn-watch
- Microsoft Security Update GuideMicrosoft Windows — CVE-2026-81963pwn-watch
- NVD (NIST)NVD: CVE-2026-81963pwn-watch
- Microsoft Security Update GuideMicrosoft Windows — CVE-2026-85880pwn-watch
- NVD (NIST)NVD: CVE-2026-85880pwn-watch
- cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch
- JPCERT/CCJPCERT/CC JPCERT-AT-2026-0025: Microsoft Releases September 2026 Security Updatesjpcert
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).
Record modifiedMicrosoft
1 individual change: Affected versions (publisher)
Show the original change
Individual changes of this event as published by NVD Type Action Before After 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
Record modifiedCISA ADP
CISA assessment (SSVC): exploitation: active, automatable: no
Show the original change
Individual changes of this event as published by NVD Type Action Before After SSVC assessment changed {"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
Initial analysis by NVDNVD
Newly listed as affected:- Microsoft Windows Server 2012 (r2)
- Microsoft Windows 10 1607 (before 10.0.14393.9512)
- Microsoft Windows 10 1809 (before 10.0.17763.9245)
- Microsoft Windows 10 21H2 (before 10.0.19044.7725)
- Microsoft Windows 10 22h2 (before 10.0.19045.7725)
- Microsoft Windows Server 2016 (before 10.0.14393.9512)
- Microsoft Windows Server 2019 (before 10.0.17763.9245)
- Microsoft Windows Server 2022 (before 10.0.20348.5622)
Show 3 original changes
Individual changes of this event as published by NVD Type Action Before After Product configuration added —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) 10.0.20348.5622Reference type added —Microsoft Corporation: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85880 Types: Patch, Vendor AdvisoryReference type added —CISA-ADP: https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-85880 Types: US Government ResourceSource identifier: nvd@nist.gov
Record modifiedCISA ADP
CISA assessment (SSVC): exploitation: active, automatable: no
Show 2 original changes
Individual changes of this event as published by NVD Type Action Before After Reference added —https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-85880SSVC assessment changed {"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
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 Type Action Before After Date Added added —2026-09-08Due Date added —2026-09-08Required Action added —2026-09-08Vulnerability Name added —2026-09-08Source identifier: 9119a7d8-5eab-497f-8521-727c672e3725
Show 2 older changes
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 Type Action Before After Description added —Heap-based buffer overflow in Windows ALPC allows an authorized attacker to elevate privileges locally.CVSS added —AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HWeakness type (CWE) added —CWE-122Weakness type (CWE) added —CWE-908Affected 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>Reference added —https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85880Source identifier: secure@microsoft.com
Record modifiedCISA ADP
CISA assessment (SSVC): exploitation: none known, automatable: no
Show the original change
Individual changes of this event as published by NVD Type Action Before After SSVC assessment added —{"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
- Microsoft Patchday September 2026: 974 Schwachstellen, zwei aktiv ausgenutztNEOSEC article
- Chinese Hackers Exploit Chrome-Windows Zero-Day Chain to Deploy CLEANGULP MalwareThe Hacker News
- Attackers are weaponizing the gap between Chromium fixes and Chrome patchesCSO Online
- NCSC-2026-0353 [1.01] [M/H] Kwetsbaarheden verholpen in Microsoft WindowsNCSC-NL
- September 2026 Patch Tuesday roundup: Plugs for two zero day holes among almost 1,000 fixes in WindowsCSO Online
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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>