Full Report
The Patch Tuesday for December of 2025 includes 57 vulnerabilities, including two that Microsoft marked as “critical.” The remaining vulnerabilities listed are classified as “important.” Microsoft assessed that exploitation of the two “critical” vulnerabilities is “less likely.”
Analysis Summary
This summary focuses on the critical and notable vulnerabilities disclosed in the Microsoft Patch Tuesday for December 2025, based on the provided context.
## Summary of December 2025 Patch Tuesday Vulnerabilities (Microsoft)
The December 2025 Patch Tuesday addressed 57 vulnerabilities, including two rated "Critical" and 55 rated "Important." Microsoft assessed the exploitation of the "critical" flaws as "less likely."
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# Vulnerability: Microsoft Outlook Remote Code Execution (Use After Free)
## CVE Details
- CVE ID: CVE-2025-62562
- CVSS Score: [Not explicitly provided, derived from "Critical" rating] (Critical)
- CWE: Use After Free (Inferred)
## Affected Systems
- Products: Microsoft Office Outlook
- Versions: [Not explicitly provided]
- Configurations: Requires the user to reply to a maliciously crafted email.
## Vulnerability Description
A Use After Free (UAF) flaw exists in Microsoft Office Outlook. Successful exploitation allows an unauthorized remote attacker to execute arbitrary code locally on the victim's system.
## Exploitation
- Status: Theoretical, requires user interaction.
- Complexity: Medium (Requires user opening/replying to a malicious email).
- Attack Vector: Network (via email)
## Impact
- Confidentiality: [Not specified]
- Integrity: Remote Code Execution
- Availability: [Not specified]
## Remediation
### Patches
- [Specific patch details not available in the text, refer to MSRC advisory.]
### Workarounds
- Users must be cautious when replying to unexpected or suspicious emails.
## Detection
- [Specific IoCs not provided]
- Detection relies on applying vendor security updates.
## References
- [Vendor advisories]: msrc.microsoft.com/update-guide/vulnerability/CVE-2025-62562
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# Vulnerability: Microsoft Office Remote Code Execution (Type Confusion/UAF)
## CVE Details
- CVE ID: CVE-2025-62553, CVE-2025-62554, CVE-2025-62556, CVE-2025-62557 (Grouped, as details are similar)
- CVSS Score: [Not explicitly provided, derived from "Critical" rating] (Critical)
- CWE: Type Confusion, Use After Free, Untrusted Pointer Dereference (Inferred)
## Affected Systems
- Products: Microsoft Office (Multiple components)
- Versions: [Not explicitly provided]
- Configurations: Successful exploitation requires the attacker to execute exploit code from the local machine.
## Vulnerability Description
Multiple flaws across Microsoft Office components (including Type Confusion, Use After Free, or Untrusted Pointer Dereference) could allow an unauthorized attacker to execute code locally. Although some were rated "critical," exploitation requires local access.
## Exploitation
- Status: Theoretical/Local execution only.
- Complexity: High (Requires local execution capability first).
- Attack Vector: Local
## Impact
- Confidentiality: Remote Code Execution
- Integrity: Remote Code Execution
- Availability: [Not specified]
## Remediation
### Patches
- [Specific patch details not available in the text, refer to MSRC advisory.]
### Workarounds
- Ensure systems are properly hardened against local execution paths.
## Detection
- [Specific IoCs not provided]
- Detection relies on applying vendor security updates.
## References
- [Vendor advisories]: msrc.microsoft.com/update-guide/vulnerability/CVE-2025-62553, msrc.microsoft.com/update-guide/vulnerability/CVE-2025-62554, msrc.microsoft.com/update-guide/vulnerability/CVE-2025-62556, msrc.microsoft.com/update-guide/vulnerability/CVE-2025-62557
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# Vulnerability: Windows Resilient File System (ReFS) Remote Code Execution
## CVE Details
- CVE ID: CVE-2025-62456
- CVSS Score: [High] (Implied based on description)
- CWE: Heap-based Buffer Overflow (Inferred)
## Affected Systems
- Products: Windows Resilient File System (ReFS)
- Versions: [Not explicitly provided]
- Configurations: Allows an *authorized* attacker to execute code over a network.
## Vulnerability Description
A heap-based buffer overflow vulnerability exists within the Windows Resilient File System (ReFS). If exploited, it could allow an authorized attacker to execute arbitrary code across the network. Microsoft assessed exploitation in the wild as unlikely, despite high CVSS scores.
## Exploitation
- Status: Unlikely in the wild (Vendor assessment).
- Complexity: [Not explicitly provided, but network RCE suggests Medium/High theoretical complexity]
- Attack Vector: Network
## Impact
- Confidentiality: Remote Code Execution
- Integrity: Remote Code Execution
- Availability: [Not specified]
## Remediation
### Patches
- [Specific patch details not available in the text, refer to MSRC advisory.]
### Workarounds
- Apply vendor security updates.
## Detection
- [Specific IoCs not provided]
- Detection relies on applying vendor security updates.
## References
- [Vendor advisories]: msrc.microsoft.com/update-guide/vulnerability/CVE-2025-62456
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# Vulnerability: Windows Routing and Remote Access Service (RRAS) RCE (User Interaction Required)
## CVE Details
- CVE ID: CVE-2025-62549
- CVSS Score: [Not explicitly provided]
- CWE: [Not specified]
## Affected Systems
- Products: Windows Routing and Remote Access Service (RRAS)
- Versions: [Not explicitly provided]
- Configurations: Requires the user to initiate a connection to a malicious server controlled by the attacker.
## Vulnerability Description
An attacker can craft malicious data delivered by a malicious server in response to a user-initiated connection request to the RRAS. This response could lead to arbitrary code execution. Exploitation is dependent on user interaction (sending a request to a malicious server).
## Exploitation
- Status: Theoretical, requires user interaction.
- Complexity: High (User must be tricked into connecting to the malicious server).
- Attack Vector: Network
## Impact
- Confidentiality: Remote Code Execution
- Integrity: Remote Code Execution
- Availability: [Not specified]
## Remediation
### Patches
- [Specific patch details not available in the text, refer to MSRC advisory.]
### Workarounds
- Educate users on only initiating connections to trusted servers via RRAS.
## Detection
- [Specific IoCs not provided]
- Detection relies on applying vendor security updates.
## References
- [Vendor advisories]: msrc.microsoft.com/update-guide/vulnerability/CVE-2025-62549
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# Vulnerability: Windows Shell Elevation of Privilege (EoP)
## CVE Details
- CVE ID: CVE-2025-62565, CVE-2025-64661 (Grouped)
- CVSS Score: [Not explicitly provided]
- CWE: Use After Free, Race Condition (Inferred)
## Affected Systems
- Products: Windows Shell
- Versions: [Not explicitly provided]
- Configurations: Requires a local, authorized attacker. Involves UAF or synchronization issues (race condition).
## Vulnerability Description
These issues permit a local, authorized attacker to gain higher privileges on the system via flaws in Windows Shell, potentially involving Use After Free or improper synchronization leading to a race condition.
## Exploitation
- Status: Theoretical (Requires local presence).
- Complexity: Medium/High (Dependent on specific flaw).
- Attack Vector: Local
## Impact
- Confidentiality: Privilege Escalation
- Integrity: Privilege Escalation
- Availability: [Not specified]
## Remediation
### Patches
- [Specific patch details not available in the text, refer to MSRC advisory.]
### Workarounds
- Restrict local user permissions where possible.
## Detection
- [Specific IoCs not provided]
- Detection relies on applying vendor security updates.
## References
- [Vendor advisories]: msrc.microsoft.com/update-guide/vulnerability/CVE-2025-62565, msrc.microsoft.com/update-guide/vulnerability/CVE-2025-64661
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# Noteworthy Important Vulnerabilities (Higher Exploitation Likelihood)
Cisco Talos highlighted several **Important** vulnerabilities that Microsoft assessed as **"more likely" to be exploited**, primarily involving **Elevation of Privilege (EoP)**.
| CVE ID | Description | Attack Vector |
| :--- | :--- | :--- |
| CVE-2025-62454 | Windows Cloud Files Mini Filter Driver EoP | Local |
| CVE-2025-62458 | Win32k EoP | Local |
| CVE-2025-62470 | Windows Common Log File System Driver EoP | Local |
| CVE-2025-62472 | Windows Remote Access Connection Manager EoP | Local |
| CVE-2025-59516, CVE-2025-59517 | Windows Storage VSP Driver EoP | Local |
| CVE-2025-62221 | Windows Cloud Files Mini Filter Driver EoP | Local |
### Remediation Summary (General)
- **Patches:** All listed CVEs require applying the corresponding updates released by Microsoft on December 2025 Patch Tuesday.
- **Detection:** Talos released new Snort rules to detect exploitation attempts: **62486, 62487, 65555-65562, 65571-65574** (Snort 2) and **300719, 301351-301354, 301356, 301357** (Snort 3).
- **Updates:** Cisco Security Firewall customers should update their SRU.
### References
- [Vendor advisories]: msrc.microsoft.com/update-guide/ (General link for full list)
- [Blog]: blog.talosintelligence.com/