CVE-1999-0341 in Linux
Summary
by MITRE
buffer overflow in the linux mail program "deliver" allows local users to gain root access.
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Analysis
by VulDB Data Team • 04/17/2026
The vulnerability identified as CVE-1999-0341 represents a critical buffer overflow flaw within the linux mail program deliver which enables local users to escalate their privileges to root access. This issue stems from inadequate input validation and memory management within the deliver utility that processes mail delivery operations. The vulnerability specifically affects systems where the deliver program is installed with setuid root permissions, creating an exploitable path for privilege escalation. The buffer overflow occurs when the program processes user-supplied data without proper bounds checking, allowing an attacker to overwrite adjacent memory locations including return addresses and system privileges.
The technical exploitation of this vulnerability relies on the fundamental principle of buffer overflow attacks where malicious input exceeds the allocated buffer space, causing information to overwrite adjacent memory regions. In this case, the deliver program's failure to validate input length before copying data into fixed-size buffers creates an opportunity for attackers to manipulate the program's execution flow. The vulnerability is particularly dangerous because it operates within a privileged context, as the deliver program runs with root permissions, meaning successful exploitation directly results in root compromise. The flaw demonstrates poor programming practices related to memory management and input sanitization that violate established security principles.
The operational impact of CVE-1999-0341 extends beyond simple privilege escalation to encompass full system compromise capabilities. Local users who can execute the deliver program can leverage this vulnerability to gain complete administrative control over affected systems, potentially leading to data exfiltration, system modification, or establishment of persistent backdoors. This vulnerability affects a wide range of unix and linux systems where the mail delivery infrastructure is configured with vulnerable versions of the deliver program. The attack vector is relatively straightforward as it requires only local access and the ability to invoke the vulnerable program, making it particularly concerning for multi-user systems where local privilege escalation can be achieved by any authenticated user.
Mitigation strategies for this vulnerability must address both the immediate security risk and prevent exploitation through proper system hardening. System administrators should immediately update or patch affected deliver implementations to ensure proper input validation and buffer size checking. The recommended approach includes removing setuid permissions from vulnerable programs when possible, or implementing proper bounds checking and input sanitization measures. Security practices should incorporate regular vulnerability assessments and ensure that all system utilities are properly configured without unnecessary privileged permissions. This vulnerability aligns with CWE-121 which describes stack-based buffer overflow conditions and relates to ATT&CK technique T1068 which covers privilege escalation through local exploits. Organizations should implement comprehensive patch management procedures and conduct regular security audits to identify and remediate similar vulnerabilities in their infrastructure. The incident underscores the importance of secure coding practices and proper privilege management in system utilities to prevent unauthorized access escalation.