CVE-2024-42391 in Mongoose Web Server
Summary
by MITRE • 11/18/2024
Use of Out-of-range Pointer Offset vulnerability in Cesanta Mongoose Web Server v7.14 allows an attacker to send an unexpected TLS packet and force the application to read unintended heap memory space.
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Analysis
by VulDB Data Team • 02/26/2025
The CVE-2024-42391 vulnerability represents a critical memory safety issue within the Cesanta Mongoose Web Server version 7.14, specifically manifesting as a use of out-of-range pointer offset flaw that can be exploited through crafted TLS communications. This vulnerability resides in the server's handling of TLS packet processing where an attacker can manipulate the TLS handshake sequence to trigger memory access violations. The flaw occurs when the web server processes unexpected TLS packets, causing it to calculate pointer offsets that extend beyond the intended heap memory boundaries. Such out-of-range memory access can result in reading uninitialized memory contents, potentially exposing sensitive data or enabling further exploitation techniques.
The technical implementation of this vulnerability stems from inadequate bounds checking within the TLS processing routines of the Mongoose web server. When the server encounters malformed or unexpected TLS packets during the secure communication establishment phase, the pointer arithmetic calculations become invalid, leading to memory access patterns that extend beyond allocated heap regions. This type of vulnerability falls under the CWE-129 category of Improper Validation of Array Index, specifically manifesting as an out-of-bounds read condition. The vulnerability is particularly dangerous in TLS contexts because it can be triggered through network-based attacks without requiring authentication or privileged access, making it a significant concern for web servers handling sensitive communications.
From an operational impact perspective, this vulnerability creates substantial risks for organizations relying on Cesanta Mongoose Web Server for secure web services, particularly those handling confidential data or serving as critical infrastructure components. The ability to read unintended heap memory spaces can potentially expose session tokens, cryptographic keys, user credentials, or other sensitive information stored in memory. Attackers can leverage this vulnerability to perform information disclosure attacks, potentially leading to complete system compromise if combined with other exploitation techniques. The vulnerability's network-based nature means that any system running the affected Mongoose version and accepting TLS connections could be at risk, regardless of local network security measures.
Mitigation strategies for CVE-2024-42391 should prioritize immediate patching of the Cesanta Mongoose Web Server to version 7.15 or later where the memory access bounds checking has been corrected. Organizations should also implement network-based monitoring to detect unusual TLS packet patterns that might indicate exploitation attempts. The vulnerability aligns with ATT&CK technique T1566.001 for Initial Access through spearphishing attachments and T1005 for Data from Local System, as it enables information disclosure from the target system. Additional defensive measures include implementing network segmentation, deploying intrusion detection systems to monitor for anomalous TLS traffic patterns, and conducting regular security assessments of web server configurations. Organizations should also consider implementing automated patch management processes to ensure timely deployment of security updates across all affected systems, as the vulnerability can be exploited remotely without requiring any special privileges or authentication credentials.