CVE-2026-76149 in CorvusSKK
Summary
by MITRE • 08/26/2026
CorvusSKK contains an integer overflow vulnerability, which may allow malicious data to be written to a dictionary file.
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Analysis
by VulDB Data Team • 08/26/2026
The security flaw identified within CorvusSKK represents a critical failure in input validation and memory management logic, specifically manifesting as an integer overflow condition during the processing of user-provided or external data intended for dictionary files. In software engineering, particularly when dealing with text-based configuration or database structures like SKK dictionaries, it is imperative that all numerical values derived from inputs are rigorously checked against their expected bounds before being used in memory allocation routines or array indexing operations. When an integer overflow occurs, the arithmetic operation exceeds the maximum value that can be represented by the allocated data type, causing the result to wrap around to a small positive number or zero rather than triggering an exception or error state as intended. This behavior is particularly dangerous because it allows the application to proceed with operations based on incorrect size calculations, effectively bypassing safety checks designed to prevent buffer overflows and unauthorized memory access.
From a technical perspective, this vulnerability aligns closely with CWE-190, which classifies integer overflow or wraparound errors as a distinct category of software weaknesses. The core issue lies in the lack of proper boundary checking before arithmetic operations are performed on values derived from external sources. In the context of CorvusSKK, if an attacker can supply data that causes a counter or size variable to overflow during the parsing or writing process for a dictionary file, they may manipulate the internal state of the application. This manipulation can lead to scenarios where memory is allocated incorrectly, potentially allowing malicious payloads to be written beyond the intended boundaries of the buffer associated with the dictionary entry. Such conditions are often precursors to more severe exploitation vectors, including arbitrary code execution or denial of service attacks, depending on how the vulnerable function interacts with the operating system and other running processes.
The operational impact of this vulnerability is significant due to its potential for remote or local exploitation through crafted input files. An attacker who can influence the content of a dictionary file loaded by CorvusSKK could exploit this integer overflow to corrupt memory structures, leading to application crashes that disrupt service availability. More critically, if the overwritten data includes control flow information such as return addresses or function pointers, it may enable remote code execution on the affected system. This poses a severe risk to users who rely on SKK for text input in professional environments where integrity and confidentiality of local systems are paramount. The ability to write malicious data directly into dictionary files also implies that persistent threats could be established if an attacker gains initial access through this vector, potentially using the compromised application as a foothold for further lateral movement within a networked environment.
Mitigation strategies must focus on implementing robust input validation and secure coding practices at both the source code level and deployment configuration levels. Developers should enforce strict type checking and range verification for all numerical inputs before they are used in arithmetic operations or memory allocation calls. Utilizing programming languages or libraries that provide automatic bounds checking can significantly reduce the risk of such vulnerabilities. Additionally, applying defense-in-depth principles by enabling compiler-level protections such as stack canaries, Address Space Layout Randomization (ASLR), and Data Execution Prevention (DEP) can mitigate the impact of successful exploitation attempts even if the underlying code flaw remains unpatched immediately. Users should be advised to update CorvusSKK to the latest patched version that addresses this integer overflow issue and to exercise caution when loading dictionary files from untrusted sources, ensuring that only verified and sanitized data is processed by the application.