Full Report
A month with no Critical-severity Windows bugs is overshadowed by a mass of Mariner mop-up
Analysis Summary
As a vulnerability research specialist, here is the actionable summary based on the provided context, focusing on the December Patch Tuesday findings:
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# Vulnerability: December Patch Tuesday Summary (Focus on High Severity and Exploited Flaws)
## CVE Details
Since specific CVE IDs and associated CVSS scores for the 56 total patches were not provided individually in the text (only aggregated counts), the following details are generalized based on the severity breakdown:
- **CVE ID:** Multiple (56 total disclosed/patched)
- **CVSS Score:** Up to 9.0+ (8 issues $\ge$ 8.0), 2 issues marked **Critical Severity** by Microsoft.
- **CWE:** Not explicitly detailed, but major issue types include Elevation of Privilege (28), Remote Code Execution (19).
## Affected Systems
- **Products:** Windows (38 CVEs), Microsoft 365 (13 CVEs), Office (13 CVEs), Excel (6), SharePoint (5), Word (4), Exchange (2), Access (1), Azure (1), GitHub (1).
- **Versions:** Multiple versions of Microsoft Office LTSC for Mac 2021 and 2024 are specifically mentioned as affected by the RCE flaws, but patches are **not yet ready** for these Mac versions. Specific versions are not listed for most Windows/Office components.
- **Configurations:** Issues are present across product families affecting operating systems, productivity suites, and cloud services.
## Vulnerability Description
The December Patch Tuesday resolved 56 CVEs across 10 product families. The good news is that **no Critical-severity bugs were found in the core Windows operating system components.** However, **two Critical-severity bugs were found in the blended Office-365 product family.** The most numerous flaws tracked were **Elevation of Privilege** vulnerabilities (28 total). Several high-severity Remote Code Execution (RCE) flaws target Microsoft Office and Word applications.
Additionally, **84 CVEs affecting CBL Mariner and/or Azure Linux** were addressed, all originating from MITRE.
## Exploitation
- **Status:**
- **One** documented vulnerability is **known to be under active exploit in the wild**.
- **Two** vulnerabilities are **publicly disclosed** (but context doesn't specify if they are exploited).
- **Six** additional CVEs are judged by Microsoft as **more likely to be exploited in the next 30 days.**
- **All 84 CBL Mariner/Azure Linux CVEs are indicated as exploited in the wild.**
- **Complexity:** Not explicitly rated for specific CVEs, but RCE and EoP flaws often imply moderate to low complexity if exploited remotely.
- **Attack Vector:** Varies, but the RCE and EoP flaws generally suggest remote or local vectors depending on the specific application context (e.g., file parsing for Office products).
## Impact
- **Confidentiality:** Affected by at least 4 disclosed Information Disclosure vulnerabilities.
- **Integrity:** Affected by 28 Elevation of Privilege and 19 Remote Code Execution flaws.
- **Availability:** Affected by 3 Denial of Service vulnerabilities.
***Note:** The seven specific RCE issues mentioned (CVE-2025-62554 through CVE-2025-62561) impacting Office/Word/Excel all carry high potential impact on Integrity.*
## Remediation
### Patches
- **56 total Microsoft patches** released to address the described issues (Windows, Office suite, Azure, GitHub).
- **14 Edge patches** (from Chromium) and **12 ColdFusion/4 Adobe Reader patches** were also released.
- **Update Status for Mac:** Patches for Microsoft Office LTSC for Mac 2021 and 2024 related to the seven RCE issues are **not yet ready**.
### Workarounds
- No specific workarounds are detailed in the summary for the main 56 CVEs. Remediation appears to rely primarily on deploying the official patches.
## Detection
- **Indicators of Compromise:** Not specified, but security teams should focus monitoring on attempts to exploit the one known in-the-wild vulnerability and the six predicted to be exploited soon.
- **Detection methods and tools:** Sophos protections are indicated as having capabilities to directly detect "various of this month’s issues." Further detection guidance for the 84 Mariner vulnerabilities is available in Appendix F (not provided here).
## References
- Vendor Advisory (Microsoft December Patch Tuesday): Link defanged due to article structure.
- Source Article: hxxps://news.sophos.com/en-us/2025/12/11/a-big-finish-to-2025-in-decembers-patch-tuesday/