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Welcome to Patch Tuesday: August 2025. Microsoft released updates addressing 107 vulnerabilities across its ecosystem this month. While some are recurring threats, a few present new angles for exploitation. These updates span critical cloud workloads, virtualization infrastructure, and database environments.
For a deeper analysis, check out the Patch [FIX] Tuesday podcast. Otherwise, take a look here to see how this Patch Tuesday stacks up.
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CVE-2025-53155 [Important]
Windows Hyper-V elevation of privilege vulnerability
CVE-2025-53155 (CVSS 7.8/10) is a Windows Hyper-V vulnerability. The flaw involves a buffer overflow triggered by a specially crafted VHDX (Virtual Hard Disk) file. When processed by Hyper-V, this file can give a local attacker elevated privileges — and potentially full system access. This is not an entirely new threat pattern. Hyper-V has faced similar elevation paths in the past, but this iteration again underscores how sensitive virtualized infrastructure can be to crafted file inputs.
It’s recommended to apply the Microsoft patch immediately across all affected Hyper-V instances. If patching must be delayed, consider isolating high-risk virtual machines and limiting untrusted VHDX file use. Monitoring for unusual privilege escalation events in your virtualization logs can also help catch active exploitation attempts early.
For environments running multiple guest systems on shared hosts, the attack surface expands. An attacker exploiting this flaw could potentially move laterally within the same physical server, affecting multiple tenants or workloads. Segmentation between VMs, along with strict control over imported virtual disks, can help reduce the likelihood of such cross-tenant impact.
– Ryan Braunstein, Security Manager, Automox
CVE-2025-49707 [Critical]
CVE-2025-49707 carries a CVSS score of 7.9/10 and targets Azure confidential virtual machines. It exploits flaws in certificate-based authentication between VMs, allowing an attacker to spoof identities and impersonate legitimate systems. Successful exploitation can lead to unauthorized access to other machines or data within the same trusted environment.
Security teams should prioritize applying Microsoft’s fix for this vulnerability. Given the risk, it’s also worth evaluating certificate management processes in Azure, rotating credentials, and enabling stricter validation settings. This vulnerability can potentially be chained with CVE-2025-53155: first gaining elevated privileges in a VM, then using spoofed certificates to pivot into broader infrastructure.
Because confidential VMs often host sensitive workloads, the exploitation of this flaw could compromise data integrity and confidentiality across an entire cloud tenant. In addition to patching, regular certificate rotation, trust boundary audits, and conditional access policies are recommended to prevent a single compromised node from affecting the rest of your Azure deployment.
– Ryan Braunstein, Security Manager, Automox
Microsoft SQL Server elevation of privilege vulnerabilities [Important]
This month includes four SQL Server vulnerabilities, each scoring CVSS 8.8/10. (CVE-2025-24999, CVE-2025-49759, CVE-2025-47954, and CVE-2025-53727). Two involve SQL injection from unsanitized parameters, while others exploit the ability to inject arbitrary T-SQL commands via specially crafted database names. In each CVE, SQL Server versions 13 through 16, including some minor releases, are impacted. The threat here is straightforward: unvalidated input can execute commands with high-level privileges, leading to data compromise or complete server takeover.
Hardening SQL environments starts with strict input validation and parameterized queries. Sanitizing all inputs before they reach the database is a foundational defense that remains relevant decades after SQL injection was first documented. This step protects against both traditional injection vectors and the newer T-SQL name-based exploit paths.
The recommended approach is to patch SQL Server to the latest supported release. If patching is delayed, implement web application firewalls or query validation layers to intercept malicious inputs. Regularly auditing query behavior and database access logs can also provide early detection of exploitation attempts. However, hardening your SQL environment is equally critical: this means limiting administrative access, segmenting database servers from direct internet exposure, enforcing least privilege for database accounts, and applying encryption to sensitive data at rest and in transit.
Even when fully patched, a poorly secured SQL instance can be a prime target for attackers.
– Mat Lee, Senior Security Engineer, Automox
Patch regularly, patch often
Each month’s Patch Tuesday serves as a reminder that vulnerabilities often repeat familiar patterns. Old attack vectors still work when systems remain unpatched or improperly configured. Regular updates, combined with security hygiene such as input validation, certificate management, and least privilege access, can significantly reduce your exposure window. Treat these releases as part of an ongoing security cycle, not a one-time task.
Until next month: patch regularly, patch often.
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