CVE-2000-0353 in Pine
Summary
by MITRE
Pine 4.x allows a remote attacker to execute arbitrary commands via an index.html file which executes lynx and obtains a uudecoded file from a malicious web server, which is then executed by Pine.
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Analysis
by VulDB Data Team • 04/19/2026
The vulnerability described in CVE-2000-0353 represents a critical remote code execution flaw in Pine email client version 4.x that demonstrates the dangerous intersection of web browser integration and local command execution capabilities. This vulnerability operates through a sophisticated attack chain that leverages the mail client's integration with web browsing functionality to deliver malicious payloads directly to the victim's system. The flaw specifically targets Pine's handling of HTML content within email messages, where the client automatically processes embedded web elements and executes associated commands without proper input validation or sanitization.
The technical exploitation mechanism involves a malicious web server hosting an index.html file that contains embedded commands designed to trigger the lynx web browser component within Pine. When a user opens an email containing this crafted HTML content, Pine automatically executes lynx to retrieve a uudecoded file from the malicious server. This file typically contains shell commands or binary executables that are then executed on the victim's system with the privileges of the user running Pine. The vulnerability stems from inadequate sandboxing and input validation within Pine's HTML processing engine, which fails to properly isolate web content from local system operations. This represents a classic case of insufficient input sanitization and improper privilege management, aligning with CWE-20 which addresses "Improper Input Validation" and CWE-78 which covers "Improper Neutralization of Special Elements used in an OS Command."
The operational impact of this vulnerability extends far beyond simple remote code execution, as it provides attackers with complete control over the victim's email client environment and potentially the underlying operating system. An attacker can leverage this vulnerability to install backdoors, steal sensitive email data, modify system configurations, or use the compromised system as a pivot point for further network reconnaissance and lateral movement. The attack requires minimal user interaction beyond opening an email message, making it particularly dangerous in corporate environments where users frequently access email containing web content. This vulnerability also demonstrates the risks associated with rich text email processing and the integration of web browsing capabilities within email applications, which creates additional attack surfaces that are often overlooked during security assessments.
Organizations should implement immediate mitigations including disabling HTML email rendering in Pine configurations, updating to patched versions of the email client, and implementing network-level restrictions to prevent access to potentially malicious web resources. Security measures should also include user education about the dangers of opening emails from untrusted sources and implementing email filtering solutions that can detect and block suspicious HTML content. The vulnerability highlights the importance of principle of least privilege and proper application sandboxing, as recommended in the MITRE ATT&CK framework under techniques related to privilege escalation and execution. Network segmentation and firewall rules should be configured to restrict outbound connections from email clients to external web servers, particularly those that might host malicious content. Regular security assessments should include testing for similar vulnerabilities in other email clients and applications that integrate web browsing capabilities, as this type of flaw remains prevalent in applications that attempt to merge email and web functionality without proper security controls.