CriticalCVE-2024-49039

Windows Task Scheduler Elevation of Privilege Vulnerability (CVE-2024-49039)

Published 12.11.2024In CISA KEV since 12.11.2024Sources: Msrc Update Guide, CVE.org, pwn.watch

What is affected, what to do

Windows Task Scheduler Elevation of Privilege Vulnerability

The vulnerability is being actively exploited; treat it as a priority. CISA lists it as used in ransomware campaigns. Update Microsoft Windows Server 2025 to version 10.0.26100.2314, Microsoft Windows Server 2025 (Server Core installation) to version 10.0.26100.2314, Microsoft Windows 10 Version 1809 to version 10.0.17763.6532. Immediate actions, mitigation and detection rules are in the runbook below.

Affected: Microsoft Windows Server 2025 lt 10.0.26100.0..10.0.26100.2314
Microsoft Windows Server 2025 (Server Core installation) lt 10.0.26100.0..10.0.26100.2314
Microsoft Windows 10 Version 1809 lt 10.0.17763.0..10.0.17763.6532
Microsoft Windows Server 2019 lt 10.0.17763.0..10.0.17763.6532
Microsoft Windows Server 2019 (Server Core installation) lt 10.0.17763.0..10.0.17763.6532
Microsoft Windows Server 2022 lt 10.0.20348.0..10.0.20348.2849
Microsoft Windows 10 Version 21H2 lt 10.0.19043.0..10.0.19044.5131
Microsoft Windows 11 version 22H2 lt 10.0.22621.0..10.0.22621.4460
Microsoft Windows 10 Version 22H2 lt 10.0.19045.0..10.0.19045.5131
Microsoft Windows 11 version 22H3 lt 10.0.22631.0..10.0.22631.4460
Microsoft Windows 11 Version 23H2 lt 10.0.22631.0..10.0.22631.4460
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) lt 10.0.25398.0..10.0.25398.1251
Microsoft Windows 11 Version 24H2 lt 10.0.26100.0..10.0.26100.2314
Microsoft Windows 10 Version 1507 lt 10.0.10240.0..10.0.10240.20826
Microsoft Windows 10 Version 1607 lt 10.0.14393.0..10.0.14393.7515
Microsoft Windows Server 2016 lt 10.0.14393.0..10.0.14393.7515
Microsoft Windows Server 2016 (Server Core installation) lt 10.0.14393.0..10.0.14393.7515
Fixed in: Microsoft Windows Server 2025 10.0.26100.2314
Microsoft Windows Server 2025 (Server Core installation) 10.0.26100.2314
Microsoft Windows 10 Version 1809 10.0.17763.6532
Microsoft Windows Server 2019 10.0.17763.6532
Microsoft Windows Server 2019 (Server Core installation) 10.0.17763.6532
Microsoft Windows Server 2022 10.0.20348.2849
Microsoft Windows 10 Version 21H2 10.0.19044.5131
Microsoft Windows 11 version 22H2 10.0.22621.4460
Microsoft Windows 10 Version 22H2 10.0.19045.5131
Microsoft Windows 11 version 22H3 10.0.22631.4460
Microsoft Windows 11 Version 23H2 10.0.22631.4460
Microsoft Windows Server 2022, 23H2 Edition (Server Core installation) 10.0.25398.1251
Microsoft Windows 11 Version 24H2 10.0.26100.2314
Microsoft Windows 10 Version 1507 10.0.10240.20826
Microsoft Windows 10 Version 1607 10.0.14393.7515
Microsoft Windows Server 2016 10.0.14393.7515
Microsoft Windows Server 2016 (Server Core installation) 10.0.14393.7515

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

Metrics

8.8

Priority

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

Source: NVD, CVSS v3

8.8

CVSS v3

Severity High on the scale from 0 to 10.

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

14.2 %

EPSS score

Elevated — model estimates 10-50% exploitation likelihood.

Source: FIRST EPSS, percentile 96.6

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: 250.43 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: 8.8 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: 8.8
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: 14.2 %; Elevated — model estimates 10-50% 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: 96.6; Critical — this CVE ranks in the top fifth of all CVEs scored today (rank ≥ 80%).
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: 12.11.2024
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: 12.11.2024
CISA assessment (SSVC): Exploitation: active · not automatable · Technical impact: total; Source: CISA Vulnrichment, as of 8 November 2024
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-287

Response and mitigation

Why act now?

Prioritisation rationale

This flaw lets code escape the AppContainer sandbox and reach privileged Task Scheduler RPC functions. That makes it the textbook second link in a browser exploit chain: a drive-by or phishing page gets renderer code execution, and this CVE lifts it to system level. It is a local vector with low complexity, no user interaction, and a scope change. It also has functional exploit code, very high exploitation likelihood, and CISA's known-ransomware-use flag. Together, these place it firmly in the emergency patch window for any endpoint fleet with web and email exposure: office clients, VDI, and jump hosts. Servers without interactive browsing can be ranked one notch lower but stay in scope, since the bug pairs with any other initial-access vector.

01
Runbook step 1
Immediate response (0-24 h)
- Deploy the Microsoft November 2024 Patch Tuesday security update to all affected Windows systems. Target builds per context: Windows 10 1507 ≥ 10.0.10240.20826, 1607 ≥ 10.0.14393.7515, 1809 ≥ 10.0.17763.6532, 21H2 ≥ 10.0.19044.5131. Look up the matching KB number per build in the Microsoft Security Update Guide. Windows Server 2016 and 2019 share the 14393 and 17763 code bases, so include them in scope.
- Verify patch level via inventory (Intune, MECM, WSUS, or the UBR value under HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion). Prioritise unpatched internet-facing clients used for web browsing.
- Update browsers and other AppContainer-hosted software (Edge, Chrome, Firefox, Office Protected View, UWP apps) immediately. This bug is typically the sandbox-escape stage that follows a renderer exploit.
- On unpatched hosts, review scheduled tasks. Diff C:\Windows\System32\Tasks and HKLM\SOFTWARE\Microsoft\Windows NT\CurrentVersion\Schedule\TaskCache against baseline for tasks created or modified since November 2024.
- If exploitation is suspected, isolate the host via EDR and treat local and cached credentials as compromised. Rotate any privileged account that logged on to the host, including the LAPS password and service accounts.
02
Runbook step 2
Mitigation layers
- Configuration: Microsoft has not documented an official workaround. Do not disable the "Schedule" service, as it is critical to the OS. The update is the only real fix.
- Endpoint hardening: Enable Defender ASR rules, notably "Block process creations originating from PSExec and WMI commands", "Block executable files from running unless they meet a prevalence, age, or trusted list criterion", and "Block untrusted and unsigned processes that run from USB". These make the post-exploitation chain harder.
- Application control: Enforce WDAC or AppLocker deny rules for execution from %LOCALAPPDATA%\Packages\*\AC\, %TEMP%, and browser download folders. This stops second-stage payloads dropped after the sandbox escape.
- IAM/least privilege: Remove local admin rights, enforce LAPS, and keep admin tiering (Tier 0/1/2) intact. This limits what a SYSTEM-level foothold can harvest for lateral movement. Turn on Credential Guard and LSA protection (RunAsPPL).
- Network: Move unpatched clients into a quarantine VLAN with restricted proxy access (category filtering, block uncategorised). Block direct egress from browser processes that bypasses the proxy.
- Browser hardening: Enforce site isolation, restrict extensions to an allowlist, and force automatic updates. This shrinks the upstream code-execution stage.
03
Runbook step 3
Detection rules
- Windows Security log: Correlate Event ID 4698 (task created) and 4702 (task updated) with process context. Treat tasks created by browser or AppContainer processes as high-fidelity. KQL: DeviceEvents | where ActionType == "ScheduledTaskCreated" | where InitiatingProcessFileName in~ ("msedge.exe","chrome.exe","firefox.exe","msedgewebview2.exe")
- Task Scheduler Operational log (Microsoft-Windows-TaskScheduler/Operational): Watch EID 106 (registered), 140 (updated), and 200/201 (action started/completed). Flag actions that point into %TEMP%, %APPDATA%, or \Packages\*\AC\, and tasks with random GUID names.
- Sysmon EID 1 / EDR process tree: Look for svchost.exe -k netsvcs -p -s Schedule spawning cmd.exe, powershell.exe, or rundll32.exe where the image was recently written by a low-integrity or AppContainer process (Sysmon EID 11). Sigma shape: ParentCommandLine|contains: '-s Schedule' AND Image|contains: ['\AppData\','\Temp\'].
- RPC telemetry: Alert on calls to the ITaskSchedulerService interface (UUID 86d35949-83c9-4044-b424-db363231fd0c) from low-integrity or AppContainer-token processes. Sources are ETW Microsoft-Windows-RPC and EDR RPC events.
- Integrity jump: Look for SYSTEM- or High-integrity processes whose ancestry traces back to a browser renderer. Defender XDR: DeviceProcessEvents | where ProcessIntegrityLevel == "System" and InitiatingProcessParentFileName in~ ("chrome.exe","firefox.exe","msedge.exe")

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

Windows Task Scheduler Elevation of Privilege Vulnerability

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

Affected products

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

Affected products
		Affected versions	Fixed in
Microsoft	Windows 10 Version 1507	`10.0.10240.0 – < 10.0.10240.20826`	`10.0.10240.20826`
Microsoft	Windows 10 Version 1607	`10.0.14393.0 – < 10.0.14393.7515`	`10.0.14393.7515`
Microsoft	Windows 10 Version 1809	`10.0.17763.0 – < 10.0.17763.6532`	`10.0.17763.6532`
Microsoft	Windows 10 Version 21H2	`10.0.19043.0 – < 10.0.19044.5131`	`10.0.19044.5131`
Microsoft	Windows 10 Version 22H2	`10.0.19045.0 – < 10.0.19045.5131`	`10.0.19045.5131`
Microsoft	Windows 11 version 22H2	`10.0.22621.0 – < 10.0.22621.4460`	`10.0.22621.4460`
Microsoft	Windows 11 version 22H3	`10.0.22631.0 – < 10.0.22631.4460`	`10.0.22631.4460`
Microsoft	Windows 11 Version 23H2	`10.0.22631.0 – < 10.0.22631.4460`	`10.0.22631.4460`
Microsoft	Windows 11 Version 24H2	`10.0.26100.0 – < 10.0.26100.2314`	`10.0.26100.2314`
Microsoft	Windows Server 2016	`10.0.14393.0 – < 10.0.14393.7515`	`10.0.14393.7515`
Microsoft	Windows Server 2016 (Server Core installation)	`10.0.14393.0 – < 10.0.14393.7515`	`10.0.14393.7515`
Microsoft	Windows Server 2019	`10.0.17763.0 – < 10.0.17763.6532`	`10.0.17763.6532`
Microsoft	Windows Server 2019 (Server Core installation)	`10.0.17763.0 – < 10.0.17763.6532`	`10.0.17763.6532`
Microsoft	Windows Server 2022	`10.0.20348.0 – < 10.0.20348.2849`	`10.0.20348.2849`
Microsoft	Windows Server 2022, 23H2 Edition (Server Core installation)	`10.0.25398.0 – < 10.0.25398.1251`	`10.0.25398.1251`
Microsoft	Windows Server 2025	`10.0.26100.0 – < 10.0.26100.2314`	`10.0.26100.2314`
Microsoft	Windows Server 2025 (Server Core installation)	`10.0.26100.0 – < 10.0.26100.2314`	`10.0.26100.2314`

Vendors and products

Affected operating systems

Affected operating systems

Windows	microsoft	windows_10_1507	—
Windows	microsoft	windows_10_1607	—
Windows	microsoft	windows_10_1809	—
Windows	microsoft	windows_10_21h2	—
Windows	microsoft	windows_10_22h2	—
Windows	microsoft	windows_11_22h2	—
Windows	microsoft	windows_11_23h2	—
Windows	microsoft	windows_11_24h2	—
Windows	microsoft	windows_server_2016	—
Windows	microsoft	windows_server_2019	—
Windows	microsoft	windows_server_2022	—
Windows	microsoft	windows_server_2022_23h2	—
Windows	microsoft	windows_server_2025	—

Weakness classes (CWE)

CWE-287Improper Authentication
Class
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
Entry at MITRE CWE-287

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 Catalog	CISA Known Exploited Vulnerability (opens in a new tab)cisa.gov	actively exploited	12.11.2024
PoC-in-GitHub (nomi-sec)	cve-2024-49039-task_scheduler_eop_reproduction (opens in a new tab)github.com	PoC (publicly reported)reported, not verified	23.07.2026

References & sources

Microsoft Security Update GuideWindows Task Scheduler Elevation of Privilege VulnerabilityVendor advisory
cisa.govknown-exploited-vulnerabilities-catalog?field_cve=CVE-2024-49039government-resource
pwn.watchpwn.watch: Microsoft November 2024: 2 actively exploited zero-dayspwn-watch
Microsoft Security Update GuideMicrosoft advisory: CVE-2024-43451pwn-watch
Microsoft Security Update GuideMicrosoft advisory: CVE-2024-49039pwn-watch
NVD (NIST)NVD: CVE-2024-43451pwn-watch
NVD (NIST)NVD: CVE-2024-49039pwn-watch
cisa.govCISA Known Exploited Vulnerabilities Catalogpwn-watch

Embed badge

Show the severity and KEV status of this vulnerability on your site – with a link back here. The image is updated hourly.

<a href="https://intel.neosec.eu/en/cve/CVE-2024-49039"><img src="https://intel.neosec.eu/badge/cve/CVE-2024-49039.svg?lang=en" alt="CVE-2024-49039 – NEOSEC Intel" height="20"></a>

What is affected, what to do

Metrics

Response and mitigation

Prioritisation rationale

Immediate response (0-24 h)

Mitigation layers

Detection rules

Detection rules

Classification under NIS2 and CRA

Description

Affected products

Vendors and products

Affected operating systems

Weakness classes (CWE)

Public exploit references

References & sources