Microsoft Windows Task Scheduler Privilege Escalation
CVE-2024-49039 is a high-severity improper authentication vulnerability in Windows Server 2025 from Microsoft, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. The record lists version 10.0.26100.2314 as the first without the flaw, so updating Windows Server 2025 to that release or later removes the exposure. CISA added it to the Known Exploited Vulnerabilities catalogue on November 12, 2024, which means attacks have been observed in the wild, including in ransomware campaigns.
Attackers are already exploiting this vulnerability, according to CISA.
What to do
- Update Windows Server 2025 to 10.0.26100.2314 or a later version.
- Update Windows Server 2025 (Server Core installation) to 10.0.26100.2314 or a later version.
- Update Windows 10 Version 1809 to 10.0.17763.6532 or a later version.
- CISA's required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- Read the advisory on msrc.microsoft.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Microsoft | Windows Server 2025 | 10.0.26100.0 up to, but not including, 10.0.26100.2314 | 10.0.26100.2314 |
| Microsoft | Windows Server 2025 (Server Core installation) | 10.0.26100.0 up to, but not including, 10.0.26100.2314 | 10.0.26100.2314 |
| Microsoft | Windows 10 Version 1809 | 10.0.17763.0 up to, but not including, 10.0.17763.6532 | 10.0.17763.6532 |
| Microsoft | Windows Server 2019 | 10.0.17763.0 up to, but not including, 10.0.17763.6532 | 10.0.17763.6532 |
| Microsoft | Windows Server 2019 (Server Core installation) | 10.0.17763.0 up to, but not including, 10.0.17763.6532 | 10.0.17763.6532 |
| Microsoft | Windows Server 2022 | 10.0.20348.0 up to, but not including, 10.0.20348.2849 | 10.0.20348.2849 |
| Microsoft | Windows 10 Version 21H2 | 10.0.19043.0 up to, but not including, 10.0.19044.5131 | 10.0.19044.5131 |
| Microsoft | Windows 11 version 22H2 | 10.0.22621.0 up to, but not including, 10.0.22621.4460 | 10.0.22621.4460 |
| Microsoft | Windows 10 Version 22H2 | 10.0.19045.0 up to, but not including, 10.0.19045.5131 | 10.0.19045.5131 |
| Microsoft | Windows 11 version 22H3 | 10.0.22631.0 up to, but not including, 10.0.22631.4460 | 10.0.22631.4460 |
| Microsoft | Windows 11 Version 23H2 | 10.0.22631.0 up to, but not including, 10.0.22631.4460 | 10.0.22631.4460 |
| Microsoft | Windows Server 2022, 23H2 Edition (Server Core installation) | 10.0.25398.0 up to, but not including, 10.0.25398.1251 | 10.0.25398.1251 |
| Microsoft | Windows 11 Version 24H2 | 10.0.26100.0 up to, but not including, 10.0.26100.2314 | 10.0.26100.2314 |
| Microsoft | Windows 10 Version 1507 | 10.0.10240.0 up to, but not including, 10.0.10240.20826 | 10.0.10240.20826 |
| Microsoft | Windows 10 Version 1607 | 10.0.14393.0 up to, but not including, 10.0.14393.7515 | 10.0.14393.7515 |
| Microsoft | Windows Server 2016 | 10.0.14393.0 up to, but not including, 10.0.14393.7515 | 10.0.14393.7515 |
| Microsoft | Windows Server 2016 (Server Core installation) | 10.0.14393.0 up to, but not including, 10.0.14393.7515 | 10.0.14393.7515 |
| Microsoft | Windows 10 1507 | before 10.0.10240.20826 | 10.0.10240.20826 |
| Microsoft | Windows 10 1607 | before 10.0.14393.7515 | 10.0.14393.7515 |
| Microsoft | Windows 10 1809 | before 10.0.17763.6532 | 10.0.17763.6532 |
| Microsoft | Windows 10 21h2 | before 10.0.19044.5131 | 10.0.19044.5131 |
| Microsoft | Windows 10 22h2 | before 10.0.19045.5131 | 10.0.19045.5131 |
| Microsoft | Windows 11 22h2 | before 10.0.22621.4460 | 10.0.22621.4460 |
| Microsoft | Windows 11 23h2 | before 10.0.22631.4460 | 10.0.22631.4460 |
| Microsoft | Windows 11 24h2 | before 10.0.26100.2314 | 10.0.26100.2314 |
Version data comes from the organisation that assigned the CVE; 1 further products are omitted here. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- ChangedThe attack can reach beyond the vulnerable component into other systems.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H. Scored by CNA (microsoft.com).
Official description
Windows Task Scheduler Elevation of Privilege Vulnerability
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CISA published its SSVC assessment (exploitation: active, automatable: no, technical impact: total).
- CVE record published.
- Added to CISA's Known Exploited Vulnerabilities catalogue.
- Deadline for US federal agencies to remediate, set by CISA.
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-49039US Government Resource
Recent Improper Authentication vulnerabilities
- 8.1 High severity
- 7.4 High severity
- 8.1 High severity
- 8.1 High severity
- 8.1 High severity
- 8.1 High severity
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