Full Report
Microsoft on Tuesday shipped fixes to address a total of 78 security flaws across its software lineup, including a set of five zero-days that have come under active exploitation in the wild. Of the 78 flaws resolved by the tech giant, 11 are rated Critical, 66 are rated Important, and one is rated Low in severity. Twenty-eight of these vulnerabilities lead to remote code execution, 21 of them
Analysis Summary
The provided context details a significant Microsoft Patch Tuesday release, including five actively exploited zero-day vulnerabilities. Since specific technical details for all 78 flaws are not present, the summary focuses primarily on the five zero-days and the general scope of the update.
# Vulnerability: Microsoft May 2025 Patch Tuesday Overview (Including Five Actively Exploited Zero-Days)
## CVE Details
This summary focuses on the five zero-days announced:
- **CVE ID:** CVE-2025-30397, CVE-2025-30400, CVE-2025-32701, CVE-2025-32706, CVE-2025-32709
- **CVSS Score & Severity:**
- CVE-2025-30397: 7.5 (Likely High)
- CVE-2025-30400: 7.8 (Likely High)
- CVE-2025-32701: 7.8 (Likely High)
- CVE-2025-32706: 7.8 (Likely High)
- CVE-2025-32709: 7.8 (Likely High)
- **CWE:** Not explicitly listed for all, but categories include Memory Corruption (CVE-2025-30397) and Elevation of Privilege (others).
## Affected Systems
- **Products:** Microsoft Windows components including Scripting Engine, Desktop Window Manager (DWM) Core Library, Common Log File System (CLFS) Driver, and Ancillary Function Driver for WinSock. Microsoft Defender for Endpoint for Linux (regarding CVE-2025-26684, mentioned briefly).
- **Versions:** Specific versions are not listed in the context, but fixes are rolled out via the May 2025 Patch Tuesday updates for affected Microsoft products.
- **Configurations:** Specific configurations are not detailed, but exploitation context implies user interaction (web page/script for CVE-2025-30397) and local access for privilege escalation scenarios.
## Vulnerability Description
Microsoft addressed 78 security flaws in the May 2025 update, 11 Critical and 66 Important. The five zero-days focus on:
1. **CVE-2025-30397 (Scripting Engine Memory Corruption):** Allows an attacker to cause memory corruption via a malicious webpage or script, potentially leading to Remote Code Execution (RCE) in the context of the logged-in user.
2. **CVE-2025-30400 (DWM Core Library EoP):** A privilege escalation vulnerability in the Desktop Window Manager Core Library.
3. **CVE-2025-32701 & CVE-2025-32706 (CLFS Driver EoP):** Two separate privilege escalation flaws in the Windows Common Log File System Driver.
4. **CVE-2025-32709 (Ancillary Function Driver for WinSock EoP):** A privilege escalation vulnerability in the driver.
## Exploitation
- **Status:** **Exploited in the wild** (All five listed CVEs).
- **Complexity:**
- CVE-2025-30397: Likely Low (Web context).
- Privilege Escalation Flaws: Unspecified, but exploitation suggests relatively low complexity for achieving local persistence/privilege gain.
- **Attack Vector:** Varies. CVE-2025-30397 suggests Network/Drive-by attack potential; others are likely Local or Adjacent for privilege escalation.
## Impact
- **Confidentiality:** Varies based on privilege gained after exploitation. RCE (CVE-2025-30397) could lead to data theft.
- **Integrity:** High potential, especially for EoP flaws where an unprivileged user can gain system integrity.
- **Availability:** Not explicitly stated, but successful exploitation on high-value systems could lead to operational downtime.
## Remediation
### Patches
- All five zero-days and the other 73 vulnerabilities are addressed via the **Microsoft May 2025 Patch Tuesday updates**.
- CISA requires federal agencies to apply these fixes by **June 3, 2025**.
- Patch status for CVE-2025-26684 (Defender for Endpoint for Linux) is also included in the release cycle.
### Workarounds
- No specific workarounds were detailed in the context for the zero-days, indicating immediate patching is the primary mitigation goal due to active exploitation.
## Detection
- **Indicators of Compromise:** Not specified in the text.
- **Detection methods and tools:** The context implies the need to deploy the May 2025 security updates immediately. Organizations should monitor for signs of privilege escalation or unauthorized code execution coinciding with the vendor advisories being released. The inclusion of all five zero-days on the CISA KEV catalog mandates immediate tracking by federal entities.
## References
- Microsoft Security Update Guide: `https://msrc.microsoft.com/update-guide/releaseNote/2025-May`
- CVE-2025-30397 Advisory Link: `https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-30397`
- CVE-2025-30400 Advisory Link: `https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-30400`
- CVE-2025-32701 Advisory Link: `https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-32701`
- CVE-2025-32706 Advisory Link: `https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-32706`
- CVE-2025-32709 Advisory Link: `https://msrc.microsoft.com/update-guide/en-US/vulnerability/CVE-2025-32709`
- CISA KEV Catalog: `https://www.cisa.gov/known-exploited-vulnerabilities-catalog`