CVE-2001-1349 in Sendmail
Summary
by MITRE
Sendmail before 8.11.4, and 8.12.0 before 8.12.0.Beta10, allows local users to cause a denial of service and possibly corrupt the heap and gain privileges via race conditions in signal handlers.
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Analysis
by VulDB Data Team • 09/26/2025
The vulnerability identified as CVE-2001-1349 represents a critical race condition flaw in sendmail versions prior to 8.11.4 and 8.12.0.Beta10, exposing systems to both denial of service and potential privilege escalation attacks. This vulnerability specifically targets the signal handling mechanisms within sendmail's codebase, creating exploitable conditions that local attackers can leverage to disrupt system operations. The race condition occurs when multiple threads or processes attempt to access shared resources simultaneously, leading to unpredictable behavior and system instability. According to CWE-362, this vulnerability maps directly to concurrent execution using shared resources, where the improper handling of signal handlers creates opportunities for malicious exploitation.
The technical implementation of this vulnerability stems from how sendmail processes asynchronous signals during critical operations, particularly when handling mail delivery and processing. When multiple signals arrive in rapid succession or when signal handlers are invoked concurrently, the software fails to properly synchronize access to shared memory regions, leading to heap corruption and potential privilege escalation. The flaw manifests when sendmail's signal handlers are interrupted or modified while in operation, causing memory corruption that can be exploited to execute arbitrary code with elevated privileges. This type of vulnerability falls under ATT&CK technique T1068, which describes "Local Privilege Escalation" through the exploitation of software vulnerabilities in system processes.
The operational impact of CVE-2001-1349 extends beyond simple denial of service, as local attackers with minimal privileges can potentially escalate their access level to gain administrative control over affected systems. The heap corruption aspect of this vulnerability means that memory management structures become compromised, potentially allowing attackers to overwrite critical system data or inject malicious code into memory segments. Systems running vulnerable sendmail versions are particularly at risk in environments where local users have access to system resources, as the attack surface expands significantly. The vulnerability affects systems where sendmail is used as the primary mail transfer agent, making it a widespread concern across enterprise networks and server environments that rely on traditional mail processing mechanisms. Organizations using these vulnerable versions face potential data integrity issues, service disruption, and unauthorized access risks that can compromise entire network infrastructures.
Mitigation strategies for CVE-2001-1349 primarily focus on immediate software updates and system hardening measures. Administrators should upgrade to sendmail versions 8.11.4 or 8.12.0.Beta10 and later, which contain patches addressing the race condition in signal handling. Additionally, implementing proper access controls and limiting local user privileges can reduce the attack surface for exploitation. System administrators should also consider implementing monitoring solutions to detect unusual signal handling patterns or memory access violations that may indicate exploitation attempts. The vulnerability demonstrates the importance of proper synchronization mechanisms in multi-threaded applications and highlights the necessity of thorough testing of signal handling code in security-critical software components. Organizations should also conduct regular vulnerability assessments to identify and remediate similar issues in other system components that may be susceptible to race condition exploits.