CVE-2000-0481 in KMail
Summary
by MITRE
Buffer overflow in KDE Kmail allows a remote attacker to cause a denial of service via an attachment with a long file name.
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Analysis
by VulDB Data Team • 04/19/2026
The vulnerability identified as CVE-2000-0481 represents a classic buffer overflow condition within the KDE Kmail email client application. This flaw specifically manifests when processing email attachments that contain excessively long file names, creating a scenario where the application fails to properly validate input length before attempting to store or process the attachment metadata. The buffer overflow occurs in the handling of file name strings within the email attachment processing pipeline, where insufficient bounds checking allows an attacker to overwrite adjacent memory locations.
This vulnerability operates at the application layer and demonstrates a fundamental weakness in input validation practices that were prevalent in software development during the late 1990s and early 2000s. The flaw falls under the Common Weakness Enumeration category of CWE-121, which encompasses stack-based buffer overflow conditions, and more specifically aligns with CWE-787, representing out-of-bounds write conditions. The technical implementation of this vulnerability exploits the difference between the allocated buffer size and the actual length of data being written, creating a scenario where attacker-controlled input can overwrite critical program memory structures.
The operational impact of this vulnerability extends beyond simple denial of service, as it represents a potential vector for more sophisticated attacks if the buffer overflow can be carefully crafted to overwrite function pointers or return addresses. When an attacker sends an email containing an attachment with an extremely long file name, the Kmail application processes this input without proper bounds checking, leading to memory corruption that typically results in application crash or termination. This behavior constitutes a denial of service condition that can be exploited repeatedly to disrupt email services for legitimate users.
From an adversarial perspective, this vulnerability aligns with ATT&CK technique T1499.004, which covers network denial of service attacks through resource exhaustion or application crashes. The attack requires minimal sophistication and can be executed remotely without authentication, making it particularly dangerous in environments where email services are critical. The vulnerability's exploitation demonstrates the importance of defensive programming practices such as input sanitization, buffer size validation, and proper memory management techniques that were not universally implemented in desktop email applications of that era.
The recommended mitigation strategies for this vulnerability include immediate application patching from KDE developers, implementation of email content filtering that limits attachment file name lengths, and deployment of network-based intrusion detection systems that can identify suspicious email patterns. Organizations should also implement regular security updates and vulnerability assessments to identify similar buffer overflow conditions in other email client applications. The remediation process should emphasize proper input validation and bounds checking in all application components that process user-supplied data, particularly in file handling and string manipulation functions. Additionally, system administrators should consider implementing email quarantine mechanisms that automatically scan and filter suspicious attachments before they reach end-user inboxes, providing an additional layer of defense against such exploitation vectors.