CVE-2026-55142 in Office
Summary
by MITRE • 07/14/2026
Numeric truncation error in Microsoft Office Word allows an unauthorized attacker to disclose information locally.
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Analysis
by VulDB Data Team • 07/15/2026
This vulnerability represents a numeric truncation error within Microsoft Office Word that enables local information disclosure by unauthorized attackers. The flaw occurs when the application processes numeric values with insufficient validation or handling, potentially leading to unexpected behavior during data processing operations. Such errors typically manifest when large numeric values are truncated or rounded to fit within predefined data type limitations, creating opportunities for attackers to exploit these inconsistencies. The vulnerability falls under the broader category of data handling flaws that can compromise system integrity and confidentiality. From a cybersecurity perspective, this issue demonstrates how seemingly minor programming errors in office applications can create significant security risks when exploited locally by malicious actors. The vulnerability may be classified under CWE-190, which specifically addresses integer overflow and unsigned integer overflow conditions, or CWE-191, dealing with integer underflow conditions. Attackers could potentially leverage this flaw to extract sensitive information from memory locations or manipulate application behavior through carefully crafted numeric inputs. The operational impact extends beyond simple information disclosure, as it may enable more sophisticated attacks such as privilege escalation or arbitrary code execution depending on the specific implementation details of the truncation logic.
The exploitation of this numeric truncation error requires local system access, making it a local privilege escalation vector that could be particularly dangerous in enterprise environments. Attackers typically need to have legitimate user access to the target system before attempting to exploit this vulnerability, which means the attack surface is limited to users who already possess some level of system privileges. However, the implications are significant because even low-privilege users might gain access to sensitive data through such vulnerabilities, especially when dealing with documents containing embedded metadata or processing sensitive numeric information. The vulnerability's impact is further amplified by the widespread use of Microsoft Office applications across various organizational environments, making it a prime target for attackers seeking to establish persistent access or extract confidential information. From an ATT&CK framework perspective, this vulnerability could be categorized under techniques such as T1059 for command and scripting interpreter usage or T1068 for exploit for privilege escalation, depending on the specific exploitation method employed.
Mitigation strategies should focus on both immediate patching and operational security measures to address this numeric truncation vulnerability. Microsoft typically releases security updates through regular patch cycles that address such implementation flaws in their software products, making timely patch management essential for protecting against exploitation attempts. Organizations should implement comprehensive endpoint protection solutions that monitor for unusual numeric processing patterns or memory access behaviors that might indicate exploitation attempts. Additionally, privileged access controls and least privilege principles should be enforced to limit the potential impact of successful exploitation, ensuring that even if an attacker can exploit this vulnerability, they cannot easily escalate privileges or access additional system resources. Security awareness training for end users remains crucial in preventing social engineering attacks that might attempt to deliver malicious documents designed to trigger this numeric truncation error during normal office application usage scenarios. Technical controls such as application whitelisting and macro security settings should be implemented to reduce the attack surface, particularly in environments where users might encounter untrusted documents containing malicious numeric data structures.