CVE-2026-69742 in Office Publisher
Summary
by MITRE • 09/09/2026
Integer overflow or wraparound in Microsoft Office Publisher allows an unauthorized attacker to execute code over a network.
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified involves a critical integer overflow condition within the core processing engine of Microsoft Office Publisher, specifically affecting how memory allocation and buffer management are handled during the parsing of document structures. This flaw arises when the application fails to properly validate arithmetic operations related to size calculations for internal data buffers. When an attacker crafts a malicious file containing specific malformed objects or embedded elements with exaggerated dimension values, the integer calculation wraps around due to exceeding the maximum value representable by the allocated variable type. Instead of triggering an error or rejecting the input, the application interprets this wrapped-around negative or small positive number as a valid size for memory allocation. This discrepancy between the intended buffer size and the actual amount of data being processed creates a classic heap-based buffer overflow scenario where more data is written to the allocated memory region than was reserved by the system.
From an operational perspective, this vulnerability allows for remote code execution without any user interaction beyond opening or previewing the malicious document in certain configurations, although typically it requires the victim to open the specially crafted file within Microsoft Office Publisher. The attacker can leverage this memory corruption to overwrite adjacent heap metadata or function pointers on the call stack. By carefully controlling the overflow payload, an unauthorized actor can redirect program execution flow to arbitrary shellcode injected into the process space. This results in a complete compromise of the host system under the context of the currently logged-in user, potentially leading to data exfiltration, installation of additional malware such as backdoors or ransomware, and lateral movement within a corporate network if the compromised machine is part of an active directory environment. The ability to execute code over a network highlights the severity of this flaw, particularly in environments where documents are frequently exchanged via email attachments or shared file repositories without rigorous sanitization at the perimeter.
This vulnerability aligns with Common Weakness Enumeration (CWE) identifiers such as CWE-190 Integer Overflow or Wraparound and CWE-787 Out-of-bounds Write, which describe the root cause of improper boundary checking leading to memory corruption. In terms of tactical mapping within the MITRE ATT&CK framework, this exploit technique corresponds to Tactic TA0002 Execution through techniques like Command and Scripting Interpreter or potentially Direct Code Injection depending on how the shellcode is delivered and executed post-exploitation. The attack vector falls under Initial Access via Spearphishing Attachment if distributed maliciously, emphasizing the need for robust input validation mechanisms within office suite applications to prevent such arithmetic errors from escalating into full system compromise.
Mitigation strategies must focus primarily on applying vendor-supplied security patches that address the underlying integer validation logic and enforce stricter bounds checking during buffer allocation processes. Organizations should ensure that Microsoft Office Publisher is updated to the latest stable version containing these fixes, as unpatched systems remain highly susceptible to automated exploitation tools circulating in threat intelligence feeds. Additionally, implementing application control policies such as AppLocker or Windows Defender Application Control can restrict the execution of unsigned scripts and binaries, thereby limiting the impact even if an exploit succeeds. Network segmentation should be employed to isolate workstations running vulnerable office software from critical infrastructure servers, reducing the blast radius of a potential breach. User awareness training is also crucial to discourage opening documents from untrusted sources, although technical controls remain the primary defense against automated network-based attacks targeting this specific vulnerability class.