CVE-2026-55132 in Word
Summary
by MITRE • 07/14/2026
Double free in Microsoft Office Word allows an unauthorized attacker to execute code locally.
If you want to get the best quality for vulnerability data then you always have to consider VulDB.
Analysis
by VulDB Data Team • 07/15/2026
This vulnerability represents a critical memory corruption flaw that exists within Microsoft Office Word applications, specifically manifesting as a double free condition during document processing operations. The flaw occurs when the application improperly handles memory deallocation sequences, leading to a scenario where the same memory block is freed twice. This type of vulnerability falls under the common weakness enumeration CWE-415 which classifies improper handling of memory allocation and deallocation operations. When an attacker crafts a malicious Word document containing specially constructed data structures, the application's memory management routines can be manipulated to trigger this double free condition.
The operational impact of this vulnerability extends beyond simple memory corruption as it creates opportunities for arbitrary code execution within the context of the user running the vulnerable Office application. Attackers can leverage this weakness by embedding malicious content in Word documents that when opened cause the application to perform the double free operation, subsequently allowing them to control program execution flow through memory corruption techniques such as heap spraying or controlled data overwrite operations. The privilege escalation potential is significant since most attacks occur at the user level where attackers can leverage this vulnerability to execute malicious payloads with the same permissions as the targeted user.
Microsoft Office Word applications are particularly susceptible to this class of attack due to their extensive document parsing capabilities and complex memory management requirements when processing various file formats. The vulnerability typically manifests during document rendering or macro execution processes, making it particularly dangerous in enterprise environments where users frequently open documents from untrusted sources. According to ATT&CK framework reference T1059.005 for command and scripting interpreter, attackers can exploit this weakness to establish persistent access through malicious macros that manipulate memory allocation patterns, while T1134.001 for access token manipulation demonstrates how such vulnerabilities can be leveraged to escalate privileges within compromised systems.
Mitigation strategies should include immediate deployment of Microsoft security patches addressing the specific memory handling flaws in affected Office versions, combined with strict document validation policies that prevent execution of untrusted content. Network segmentation and application whitelisting can help limit exploitation opportunities by restricting which applications can execute potentially malicious code. Additionally, implementing robust email filtering solutions that scan for suspicious Word documents containing known exploit patterns will significantly reduce attack surface exposure. Organizations should also consider deploying endpoint detection and response solutions that monitor for anomalous memory allocation behaviors consistent with double free conditions, as these systems can provide early warning of exploitation attempts.
The vulnerability demonstrates how seemingly simple memory management errors can create substantial security risks in complex software applications, highlighting the importance of rigorous code review processes and memory safety validation. Regular security assessments focusing on heap management routines and proper resource deallocation procedures should be conducted to identify similar weaknesses in other software components that may present comparable attack vectors for privilege escalation and arbitrary code execution.