CVE-2006-3242 in Mutt
Summary
by MITRE
Stack-based buffer overflow in the browse_get_namespace function in imap/browse.c of Mutt 1.4.2.1 and earlier allows remote attackers to cause a denial of service (crash) or execute arbitrary code via long namespaces received from the IMAP server.
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Analysis
by VulDB Data Team • 06/21/2025
The vulnerability described in CVE-2006-3242 represents a critical stack-based buffer overflow within the Mutt email client's IMAP browsing functionality. This flaw exists in the browse_get_namespace function located in imap/browse.c of Mutt versions 1.4.2.1 and earlier, where the application fails to properly validate the length of namespace data received from IMAP servers during the browsing process. The vulnerability arises from inadequate input sanitization when processing namespace information, creating a condition where maliciously crafted namespace data can overflow the allocated stack buffer and potentially overwrite adjacent memory regions.
The technical implementation of this vulnerability demonstrates a classic stack overflow scenario where the application uses a fixed-size buffer to store namespace information without proper bounds checking. When an IMAP server sends namespace data exceeding the predetermined buffer size, the excess data overflows into adjacent stack memory, potentially corrupting the stack frame and execution context. This condition can be exploited by remote attackers who control the IMAP server, allowing them to craft malicious namespace responses that trigger the buffer overflow during normal email browsing operations. The vulnerability specifically affects the stack-based memory allocation pattern where the buffer is allocated on the stack rather than the heap, making it particularly susceptible to exploitation through controlled input manipulation.
The operational impact of this vulnerability extends beyond simple denial of service to encompass potential arbitrary code execution capabilities. While the primary effect manifests as application crashes and service disruption, the stack overflow condition creates opportunities for attackers to manipulate the execution flow through carefully crafted input that can overwrite return addresses, function pointers, or other critical execution context elements. This allows for remote code execution in the context of the Mutt process, potentially enabling attackers to gain unauthorized access to systems processing email through the vulnerable client. The vulnerability affects all users who rely on Mutt's IMAP browsing capabilities and exposes them to remote exploitation without requiring authentication or special privileges beyond control of the target IMAP server.
Mitigation strategies for CVE-2006-3242 should prioritize immediate patching of affected Mutt versions to the latest stable releases that contain proper input validation and buffer size enforcement. Organizations should implement network segmentation and access controls to limit exposure to untrusted IMAP servers, particularly when processing email from external sources. The implementation of input validation controls and bounds checking within the application code represents the fundamental solution to prevent this class of vulnerability, aligning with CWE-121 stack-based buffer overflow prevention requirements. Additionally, monitoring for unusual namespace data patterns and implementing intrusion detection systems can help identify exploitation attempts targeting this vulnerability. Security hardening measures including stack canaries, address space layout randomization, and non-executable stack protections should be considered as additional layers of defense, though these provide limited protection against this specific vulnerability due to its nature. The ATT&CK framework categorizes this vulnerability under privilege escalation and code execution techniques, specifically mapping to T1059 command and scripting interpreter and T1068 local privilege escalation, highlighting the potential for further attack progression once initial exploitation is achieved.