CVE-2023-45925 in Midnight Commander
Summary
by MITRE • 03/27/2024
GNU Midnight Commander 4.8.29-146-g299d9a2fb was discovered to contain a NULL pointer dereference via the function x_error_handler() at tty/x11conn.c. NOTE: this is disputed because it should be categorized as a usability problem (an X operation silently fails).
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Analysis
by VulDB Data Team • 06/05/2024
The vulnerability identified as CVE-2023-45925 affects GNU Midnight Commander version 4.8.29-146-g299d9a2fb and involves a NULL pointer dereference within the x_error_handler() function located in tty/x11conn.c. This flaw represents a critical issue in the application's handling of X11 connections and error management, particularly when the software operates in graphical environments where X Window System integration is required. The vulnerability manifests when the application encounters certain X11 error conditions that trigger the error handler function without proper null pointer validation, potentially leading to application crashes or unexpected termination during normal operation.
The technical implementation of this vulnerability stems from inadequate input validation within the X11 error handling mechanism of the Midnight Commander's terminal interface. When the x_error_handler() function is invoked during X11 communication, it attempts to process error information without verifying whether the pointer references are valid or null. This particular flaw aligns with CWE-476 which specifically addresses NULL pointer dereference conditions in software implementations. The error handler's failure to properly validate pointer states creates an exploitable condition where malicious or unexpected X11 error sequences can cause the application to terminate abruptly, disrupting user workflows and potentially leading to data loss or session interruption.
From an operational perspective, this vulnerability impacts the reliability and stability of GNU Midnight Commander when operating in environments that require X11 integration, particularly in graphical terminal sessions or remote desktop environments. The reported classification as a usability problem rather than a security vulnerability reflects the limited attack surface and the fact that the application silently fails rather than exposing exploitable functionality. However, this behavior still constitutes a significant operational risk in production environments where system uptime and user productivity are critical factors. The vulnerability affects users who rely on the application's graphical capabilities and can lead to unexpected application termination during file operations or system navigation tasks.
The impact of this vulnerability extends beyond simple application stability concerns, as it can affect user confidence in the software's reliability and potentially create denial-of-service conditions in automated or continuous operation scenarios. While the specific nature of the flaw suggests it may not provide direct access to underlying system resources or enable privilege escalation, the potential for application crashes in critical operational contexts makes it a serious concern for system administrators and users who depend on stable file management capabilities. The vulnerability's classification as a usability problem by some security researchers indicates that the primary impact is functional rather than security-related, though the operational consequences remain significant for mission-critical deployments.
Mitigation strategies for this vulnerability should focus on implementing proper input validation and error handling within the affected code segment. System administrators should ensure that all instances of GNU Midnight Commander are updated to versions that address this NULL pointer dereference issue, particularly in environments where X11 integration is commonly used. The fix should involve adding null pointer checks within the x_error_handler() function to prevent dereferencing invalid pointers during X11 error processing. Additionally, users should be advised to avoid using the graphical X11 interface when possible, or to ensure their X11 environment is properly configured to minimize the likelihood of triggering this error condition. Organizations should monitor for patched versions and implement regular update procedures to maintain system integrity and prevent potential exploitation scenarios that could arise from similar error handling flaws. The vulnerability demonstrates the importance of robust error handling in graphical applications and the need for comprehensive testing of edge cases in X11 integration scenarios.