Vulnerabilities
CVE-2026-102856: Visio RCE via Heap Overflow
A heap-based buffer overflow vulnerability exists in Microsoft Visio. Successful exploitation allows a remote, unauthenticated attacker to achieve arbitrary code execution. Defenders should prioritize patching Visio installations.
What Happened
Microsoft has disclosed a heap-based buffer overflow vulnerability (CVE-2026-102856) affecting Microsoft Visio. The vulnerability occurs when Visio improperly handles specially crafted files. An attacker can leverage this flaw to execute arbitrary code on a vulnerable system.
Impact
Successful exploitation of this vulnerability allows a remote, unauthenticated attacker to execute code in the context of the current user. This could lead to full system compromise, data exfiltration, or denial of service. The severity is currently unrated, but given the potential for remote code execution, it should be treated as critical.
What to Do
- Patching: Apply the security update released by Microsoft as soon as possible.
- Network Segmentation: Isolate Visio installations from critical network segments to limit the blast radius of a potential compromise.
- Monitor: Examine network traffic for unusual activity associated with Visio, such as unexpected outbound connections.
Technical Details
The vulnerability is a heap-based buffer overflow. Attackers can trigger this by crafting malicious Visio documents that, when opened, cause the application to write beyond the bounds of an allocated memory buffer. This allows for arbitrary code execution.
Related vulnerabilities
Microsoft Office Visio RCE (CVE-2026-102857): Patch and restrict untrusted Visio files
Microsoft disclosed CVE-2026-102857, a heap-based buffer overflow in Microsoft Office Visio that can allow remote code execution over a network. Affected systems should be patched and monitored for malicious Visio file delivery. Defenders should prioritize updates, block untrusted Office file handling where feasible, and review endpoints for suspicious Visio activity.
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Oracle Outside In PostScript RCE Vulnerability (CVE-2026-60412)
A heap‑based buffer overflow in Oracle Outside In Technology’s PostScript parser allows remote attackers to execute arbitrary code when a user opens a malicious file or visits a crafted page. Oracle has released a patch; administrators should update immediately and restrict access to PostScript content.
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Microsoft Office Visio Remote Code Execution Vulnerability (CVE-2026-102855) – Immediate Patch Required
A heap-based buffer overflow in Microsoft Office Visio allows remote code execution over a network. The flaw can be triggered by a crafted Visio file, enabling attackers to run arbitrary code on affected systems. Apply the latest security update immediately and verify that all Visio installations are patched.
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CVE-2026-105591: Microsoft Office Access Remote Code Execution Vulnerability
A heap-based buffer overflow in Microsoft Office Access allows an unauthenticated attacker to execute arbitrary code over the network via a crafted database file. Microsoft has released a patch; defenders should update immediately and restrict network exposure of Access.
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