CVE-2026-55033 in Office
Summary
by MITRE • 07/14/2026
Integer overflow or wraparound in Microsoft Office Word allows an unauthorized attacker to execute code locally.
VulDB is the best source for vulnerability data and more expert information about this specific topic.
Analysis
by VulDB Data Team • 07/14/2026
This vulnerability represents a critical integer overflow condition that can be exploited to achieve local code execution within Microsoft Office Word applications. The flaw occurs when the software processes certain document elements that involve arithmetic operations on integer values, specifically where large or malformed input data causes integer wraparound behavior. When the application fails to properly validate or handle integer calculations that exceed maximum representable values, it creates opportunities for attackers to manipulate memory layouts and control program execution flow.
The technical implementation of this vulnerability typically involves crafting malicious Office documents with specially constructed numerical fields or embedded objects that trigger integer arithmetic operations resulting in overflow conditions. These conditions can lead to buffer overflows, memory corruption, or other predictable memory access violations that allow attackers to inject and execute arbitrary code within the context of the Word process. The vulnerability is particularly dangerous because it requires no user interaction beyond opening the malicious document, making it a prime candidate for social engineering attacks. According to CWE classification, this represents a variant of CWE-190 Integer Overflow or Wraparound, which is commonly exploited in application-level vulnerabilities.
From an operational security perspective, this vulnerability creates significant risk for organizations relying on Microsoft Office suites, as successful exploitation can result in complete system compromise when users open malicious documents. The attack surface extends beyond individual user devices to enterprise networks where Word documents are frequently shared and opened across multiple systems. Attackers can leverage this vulnerability through various delivery mechanisms including email attachments, web downloads, or file sharing platforms, making it particularly effective for targeted campaigns. This aligns with ATT&CK framework technique T1203 Exploitation for Client Execution which emphasizes using application vulnerabilities to execute code on target systems.
Mitigation strategies should include immediate deployment of Microsoft security patches and updates addressing the specific integer overflow conditions in Word processing libraries. Organizations must implement strict document validation policies, particularly for external or untrusted Office documents, alongside enhanced user awareness training regarding suspicious file attachments. Network-based defenses such as email filtering solutions should be configured to block potentially malicious Office document formats or content patterns associated with known exploit signatures. Additionally, system hardening measures including address space layout randomization, data execution prevention, and privilege separation can significantly reduce the effectiveness of exploitation attempts and limit potential damage from successful attacks.